File No. 70-9047

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
              ----------------------------------------------------

                      PRE-EFFECTIVE AMENDMENT NO. 1 TO THE
                                    FORM U-1
                           APPLICATION OR DECLARATION
                                    UNDER THE
                   PUBLIC UTILITY HOLDING COMPANY ACT OF 1935
              ----------------------------------------------------

                               UNITIL CORPORATION
                               6 Liberty Lane West
                          Hampton, New Hampshire 03842
               (Name of company or companies filing this statement
                   and address of principal executive offices)


                                  Gail A. Siart
                                    Treasurer
                               UNITIL CORPORATION
                               6 Liberty Lane West
                          Hampton, New Hampshire 03842
                     (Name and address of agent for service)

                  The Commission is requested to mail copies of
                   all orders, notices and communications to:

                              William S. Lamb, Esq.
                     LeBoeuf, Lamb, Greene & MacRae, L.L.P.
                              125 West 55th Street
                          New York, New York 10019-5389



Item 1. DESCRIPTION OF PROPOSED TRANSACTION

         A.    Request for  Authority  for the Company to Guarantee  Unitil
               Realty  Corp.'s  Obligations  Under  a  Long-term  Note  Purchase
               Agreement

     Unitil  Corporation,  a New Hampshire  corporation (the  "Company"),  and a
registered holding company under the Public Utility Holding Company Act of 1935,
as amended (the "Act") hereby files this  Amendment No. 1 to its  Declaration on
Form U-1 (File No. 70-9047) (the "Declaration")  seeking  authorization from the
Securities and Exchange  Commission (the  "Commission")  under Section 12 of the
Act and Rule 45  thereunder in  connection  with the Company's  guarantee of the
obligations of its subsidiary,  Unitil Realty Corp.  ("Unitil Realty"),  under a
long-term Note Purchase Agreement to be entered into for the permanent financing
of the new corporate office facility.

     The Company's  former corporate  headquarters in Exeter,  New Hampshire was
taken by  eminent  domain  by the  State of New  Hampshire  in  February,  1995,
necessitating relocation to a new corporate headquarters. In August 1996, Unitil
Realty completed construction of a new corporate office facility in Hampton, New
Hampshire (the "Facility") at a cost of approximately  $9,000,000.  The Facility
consists  of a 42,000  square  foot Class A office  building,  a 400 square foot
maintenance facility, and a parking lot for approximately 200 cars, all situated
on a 12.2 acre tract of land in the Liberty Lane business  park in Hampton,  New
Hampshire. Unitil Service, the Company's service company subsidiary, is the only
tenant of the Facility.

     Unitil  Service  occupied  the Facility in August,  1996,  and is currently
paying rent under the terms of the 1987 lease  governing its lease of the former
office  building,  as  amended.  The 1987 lease  provides  for payment by Unitil
Service to Unitil  Realty at cost.  Unitil  Realty and Unitil  Service  have now
negotiated a new long-term  lease for the Facility (the "1996 Lease").  The 1996
Lease  provides  for  payment  by Unitil  Service to Unitil  Realty at cost,  in
accordance with the Act and the rules  promulgated  thereunder.  The term of the
1996 Lease is 20 years from the date of execution, which is expected to be on or
about June 15, 1997.  Unitil Service also will have the right to extend the term
of the lease in  accordance  with the terms of the 1996 Lease.  (A draft form of
the 1996 Lease is attached as Exhibit B-1.)

     Unitil Realty has received a commitment from American United Life Insurance
Company ("American United") to provide long-term debt financing for the Facility
totaling  $7,500,000 (the  "Financing") at an annual interest rate of 8.00%. The
Financing will replace the short-term  borrowings through which Unitil Realty is
currently  financing a portion of its ownership of the Facility as authorized by
the  Commission  (HCAR No.  35-26328,  July 11,  1995),  and  provide  permanent
financing for the Facility.  The term of the Financing is 20 years,  and will be
amortized  based on level monthly  principal  and interest  payments over the 20
year  life of the  loan  (self-liquidating).  (A copy of the  commitment  letter
between  American  United,  the Company and Unitil Realty is attached as Exhibit
B-2.)

     In order for Unitil  Realty to obtain the most  favorable  financing  rate,
American United requires that the Company guarantee Unitil Realty's  obligations
under the Note and Note  Purchase  Agreement  (the  "Guarantee").  The Guarantee
covers Unitil Realty's  obligations under the Note and Note Purchase  Agreement.
Under the Note  Purchase  Agreement,  Unitil  Realty is obligated to pay a fixed
monthly  principal  and  interest  payment to  American  United.  The  estimated
aggregate net present value of the payments and other obligations under the Note
and Note Purchase Agreement does not exceed $12,000,000.

     The Company hereby  requests  authorization  from the Commission to issue a
guarantee to American United of Unitil Realty's  obligations  under the Note and
Note Purchase  Agreement in an amount up to $12,000,000,  in connection with the
Financing of the Facility.

         B.       Involvement of UNITIL System Companies with Exempt Wholesale
                  Generators and Foreign Utility Companies

     Neither the  Company  nor any  subsidiary  thereof  presently  has, or as a
consequence  of the proposed  transaction  will have,  an interest in any exempt
wholesale generator ("EWG") or foreign utility company ("FUCO"),  as those terms
are defined in Sections 32 and 33 of the Act, respectively. None of the proceeds
from the proposed  transactions  will be used by the Company nor any  subsidiary
thereof to acquire  any  securities  of, or any  interest  in, an EWG or a FUCO.
Moreover, neither the Company nor any subsidiary thereof is, or as a consequence
of the proposed  transaction  will become,  a party to, and such entities do not
and will not have any rights under, a service,  sales or construction  agreement
with any EWGs or FUCOs  except in  accordance  with the  rules  and  regulations
promulgated by the Commission with respect thereto. All applicable  requirements
of Rule 53(a)-(c), 17 C.F.R. ss.250.53(a), (b) and (c) are satisfied as required
by Rule 54 and, in any event,  the Company  does not own any interest in any EWG
or FUCO.

Item 2.           FEES, COMMISSIONS AND EXPENSES

     The fees,  commissions  and expenses of the Company  expected to be paid or
incurred,  directly or indirectly, in connection with the guarantee described in
this Declaration are estimated as follows:

Legal fees...............................................................$5,000

Item 3.           APPLICABLE STATUTORY PROVISIONS

     The Company  considers  that acting as  guarantor  for the  obligations  of
Unitil  Realty as set forth in Item 1 hereof is  subject to  Sections  12(b) and
12(f) of the Act and Rule 45 thereunder.  Unitil Realty is not seeking  approval
for the permanent  financing of the  Headquarters,  pursuant to the exemption in
Rule 52(b).

     It is  expected  that  the  proposed  transaction  will be  carried  out in
accordance  with procedure  specified in Rule 23 and pursuant to an order of the
Commission in respect thereto.

     To the extent  that the  transactions  described  in this  Declaration  are
considered  by the  Commission to require  authorization,  approval or exemption
under  any  section  of  the  Act or  the  rules  thereunder  other  than  those
specifically  referred to in this Declaration,  the Company hereby requests such
authorization, approval or exemption.

Item 4.           REGULATORY APPROVALS

     The proposed  transaction is not subject to the  jurisdiction  of any state
commission or any federal commission other than the Commission.

Item 5.           PROCEDURE

     On May 23, 1997, the Commission  issued the requisite  notice under Rule 23
with respect to the filing of this Declaration.

     It is submitted that a recommended  decision by a hearing  officer or other
responsible  officer of the  Commission  is not  necessary  or  required in this
matter.  The Division of Investment  Management of the  Commission may assist in
the preparation of the Commission's  decision in this matter. There should be no
thirty-day  waiting  period  between the issuance and the effective  date of any
order issued by the Commission in this matter, and it is respectfully  requested
that any such order be made effective immediately upon the entry thereof.

 Item 6. EXHIBITS AND FINANCIAL STATEMENTS

          a.       Exhibits

          B-1      Draft Form of Lease between Unitil Realty and Unitil Service
                   (previously filed)

          B-2      Letter of Financing Commitment from American United 
                   (previously filed)

          F-1      Opinion of Counsel (filed herewith)

          G-1      Financial Data Schedule (previously filed)

          H-1      Proposed Form of Public Notice (previously filed)

          b.       Financial Statements

          (1)      Unitil Corporation and Subsidiary Companies
                   Consolidated Balance Sheets, March 31, 1997
                   (incorporated by reference to the Form 10-Q of Unitil
                   Corp. filed on May 14, 1997 (File No. 1-8858))

          (2)      Unitil Corporation and Subsidiary Companies
                   Consolidated Statements of Earnings, March 31,
                   1997 (incorporated by reference to the Form 10-Q
                   of Unitil Corp. filed on May 14, 1997 (File No. 1-
                   8858))

          (3)      Unitil Corporation and Subsidiary Companies
                   Notes to Consolidated Financial Statements
                   (incorporated by reference to the Form 10-Q of
                   Unitil Corp. filed on May 14, 1997 (File No. 1-
                   8858))


Item 7.           INFORMATION AS TO ENVIRONMENTAL EFFECTS

     None of the  matters  that are the  subject of this  Declaration  involve a
"major  Federal  action"  nor do they  "significantly  affect the quality of the
human  environment" as those terms are used in section 102(2)(C) of the National
Environmental  Policy Act. None of the transactions that are the subject of this
Declaration  will result in changes in the  operation  of the company  that will
have an impact  on the  environment.  The  Company  is not aware of any  Federal
agency which has prepared or is preparing an environmental impact statement with
respect to the transactions which are the subject of this Declaration.


                                    SIGNATURE

     Pursuant to the  requirements  of the Public Utility Holding Company Act of
1935, the undersigned company has duly caused this amendment to be signed on its
behalf by the undersigned thereunto duly authorized.

                                            Unitil Corporation

                                            By:     /s/ Gail A. Siart
                                                    Gail A. Siart
                                                    Secretary and Treasurer
                                                     Unitil Corporation



Date:  June 25, 1997


                     LeBoeuf, Lamb, Greene & MacRae, L.L.P.
                               260 Franklin Street
                                Boston, MA 02110





                                        June 25, 1997



Securities and Exchange Commission
450 Fifth Street, N.W.
Washington, DC  20549

Gentlemen:

     This opinion is furnished to the  Securities and Exchange  Commission  (the
"Commission")  in  connection  with  the  filing  with  the  Commission  of  the
Declaration on Form U-1 (File  70-9047) of Unitil  Corporation  (the  "Company")
under the Public  Utility  Holding  Company Act of 1935. The  Declaration  seeks
approval for the guarantee by the Company of the  obligations of its subsidiary,
Unitil Realty Corp., under a note and note purchase agreement.

     We have  acted as  counsel  for the  Company  and in  connection  with this
opinion we have examined  originals or copies certified or otherwise  identified
to our satisfaction of:

                  (1)  The charter documents and by-laws of the Company, as
         amended to date;

                  (2)  Minutes of meetings of the Company's shareholders and
         directors, as kept in their respective minute books;

                  (3) The documents and  agreements  pertaining to the guarantee
         described in the Declaration and such other certificates, documents and
         papers  as we  deemed  necessary  or  appropriate  for the  purpose  of
         rendering this opinion.

     In such examination, we have assumed the genuineness of all signatures, the
authenticity of all documents submitted to us as originals and the conformity to
the original  documents of all  documents  submitted to us as copies.  As to any
facts  material  to  our  opinion,   we  have,  when  relevant  facts  were  not
independently  established,  relied upon the aforesaid agreements,  instruments,
certificates and documents.  In addition, we have examined such questions of law
as we  considered  necessary or  appropriate  for the purpose of rendering  this
opinion.

     Based on the foregoing,  and subject to the final paragraph  hereof, we are
of the opinion that when the  Commission  has taken the action  requested in the
Declaration:

         (1)      All state laws applicable to the guarantee described in
                  the Declaration have been complied with;

         (2)      The Company is validly organized and duly existing;

         (3)      When issued as described in the Declaration,  the guarantee by
                  the  Company  will be a valid and  binding  obligation  of the
                  Company,  in  accordance  with its  terms,  subject to laws of
                  general  application  with  respect to rights and  remedies of
                  creditors and subject to equitable principles; and

         (4)      The consummation of the guarantee described in the Declaration
                  will not  violate  the  legal  rights  of the  holders  of any
                  securities issued by the Company.

     We  hereby  consent  to the  use  of  this  opinion  as an  exhibit  to the
Declaration.

     We are not,  in this  opinion,  opining  on laws other than the laws of the
State of New Hampshire and the federal laws of the United States.


                                      Very truly yours,

                                      /s/ LeBoeuf, Lamb, Greene & MacRae, L.L.P.

                                      LeBoeuf, Lamb, Greene & MacRae, L.L.P.