CHAPMAN AND CUTLER LLP
                             111 WEST MONROE STREET
                                CHICAGO, IL 60603


                                January 4, 2019


Securities and Exchange Commission
100 F Street, N.E.
Washington, D.C.  20549


          Re: Guggenheim Defined Portfolios, Series 1845 (the "Fund")
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Ladies and Gentlemen:

     Enclosed please find a copy of Amendment No. 1 the Registration Statement
on Form S-6 for the registration under the Securities Act of 1933 of Units
representing the ownership of interests in the subject Fund. This Amendment No.
1 Registration Statement is filed on January 4, 2019, on behalf of Guggenheim
Funds Distributors, LLC (the "Sponsor").

     Inasmuch as the Fund is not yet operative, no filings have been required
under any of the acts administered by the Commission. Therefore, for purposes of
Securities Act Release No. 5196 there are no delinquencies to be reported or
other references to be made to filings under the 1934 Act.

     No notification of registration or Registration Statement under the
Investment Company Act of 1940 is currently being submitted to the Commission,
as the filings under the 1940 Act (File No. 811-03763) are intended to apply not
only to that series of the Fund, but to all "subsequent series" as well.

     The Fund is expected to be comprised of the following unit investment
trust: Alerian MLP Infrastructure & Income Portfolio, Series 5. In its operation
and structure, the Fund is substantially similar to the prior series of
Guggenheim Defined Portfolios, Series 1810, previously filed with the Commission
on October 5, 2018.

     We are advised that the Sponsor proposes to deposit securities and to
activate the subject Fund as soon as practicable after the effective date of the
Registration Statement. An appropriate amendment to the Registration Statement
to reflect such deposit is expected to be filed with the Commission at that time
pursuant to Rule 487 under the Securities Act of 1933.

     In the event that you may have any questions with regard hereto or if there
is any way which we can be of assistance, please do not hesitate to telephone
Eric F. Fess collect at (312) 845-3781 or Morrison C. Warren at (312) 845-3484.

                                                               Very truly yours,

                                                      /s/ Chapman and Cutler LLP
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                                                          CHAPMAN AND CUTLER LLP