<PAGE>
OCTOBER 15, 1994
SECURITIES AND EXCHANGE COMMISSION
450 FIFTH STREET, N.W.
WASHINGTON, D.C. 20549
RE:RULE 24f-2 NOTICE--
NUVEEN TAX-EXEMPT UNIT TRUST, Series 691
(VA 279, MD 287, AZ INS 029, MI INS 050, MA INS 105, NJ INS 167)
FILE NO. 33-49655
DEAR SIR OR MADAM:
IN ACCORDANCE WITH THE PROVISIONS OF RULE 24f-2, JOHN NUVEEN & CO.
INCORPORATED, SPONSOR OF THE ABOVE REFERENCED SERIES OF THE NUVEEN
TAX-EXEMPT UNIT TRUST, HEREBY FILES THE RULE 24f-2 NOTICE FOR SUCH
SERIES FOR THE PERIOD ENDED SEPTEMBER 30, 1994.
SECURITIES OF SUCH SERIES HAVING THE AGGREGATE VALUE SHOWN BELOW WERE
SOLD DURING THE FISCAL YEAR IN RELIANCE UPON THE REGISTRATION OF AN
INDEFINITE AMOUNT OF SECURITIES UNDER RULE 24f-2. ATTACHED TO THIS
NOTICE, AND MADE A PART OF HEREOF, IS AN OPINION OF COUNSEL INDICATING
THAT THE SECURITIES, THE REGISTRATION OF WHICH THIS NOTICE MAKES DEFINITE
IN NUMBER, WERE LEGALLY ISSUED, FULLY PAID, AND NON-ASSESSABLE.
IN ACCORDANCE WITH SUBSECTION (C) OF RULE 24f-2, A CERTIFIED CHECK IS
ENCLOSED, WHICH REPRESENTS THE REGISTRATION FEE FOR THE SECURITIES OF
THE REFERENCED SERIES DERIVED IN ACCORDANCE WITH THE PROVISIONS OF THE
RULE AS SET FORTH BELOW, TOGETHER WITH THE FEES FOR CERTAIN OTHER SERIES
FOR WHICH RULE 24f-2 NOTICES ARE BEING SUBMITTED CONCURRENTLY HEREWITH.
THE REGISTRATION FEE FOR THIS SERIES WAS COMPUTED AS FOLLOWS:
1. DOLLAR AMOUNT RECEIVED FOR UNITS SOLD DURING THE
FISCAL YEAR $ 501,003.53
2. LESS: AGGREGATE REPURCHASE PRICE OF UNITS REDEEMED
DURING THE FISCAL YEAR $ 331,059.60
3. DOLLAR AMOUNT OF UNITS UPON WHICH FEE IS PAYABLE $ 169,943.92
4. FEE (ONE TWENTY-NINTH OF 1.0% OF ITEM 3). $ 58.63
ANY QUESTIONS REGARDING THIS NOTICE SHOULD BE DIRECTED TO MY ATTENTION.
VERY TRULY YOURS,
JOHN NUVEEN & CO. INCORPORATED
/S/JAMES J. WESOLOWSKI
JAMES J. WESOLOWSKI
VICE PRESIDENT
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OCTOBER 15, 1994
SECURITIES AND EXCHANGE COMMISSION
450 FIFTH STREET, N.W.
WASHINGTON, D.C.
RE:RULE 24F-2 NOTICE FILED WITH RESPECT TO THE DESCRIBED SERIES OF THE
NUVEEN TAX-EXEMPT UNIT TRUST
-------------------------------------------------------------------
DEAR SIR OR MADAM:
I AM COUNSEL TO JOHN NUVEEN & CO. INCORPORATED, SPONSOR OF THE VARIOUS
SERIES OF THE NUVEEN TAX-EXEMPT UNIT TRUST, AND HAVE ADVISED IT IN
CONNECTION WITH ITS FILING FOR THE SERIES LISTED BELOW OF THE NOTICES
REQUIRED BY RULE 24F-2 FOR THE PERIOD ENDED SEPTEMBER 30, 1994, WHICH BY
THEIR TERMS UNDER THE RULE MAKE DEFINITE THE REGISTRATION OF UNITS OF
INTEREST IN EACH SUCH SERIES. I AM FAMILIAR WITH THE REGISTRATION
STATEMENT OF EACH SERIES FILED ON FORM S-6 AND ALL AMENDMENTS THERETO,
AND WITH THE PROCEDURES TAKEN AND PROPOSED TO BE TAKEN BY EACH SERIES
WITH RESPECT TO THE AUTHORIZATION, ISSUANCE AND SALE OF THE UNITS.
RULE 24F-2 NOTICES ARE BEING FILED CONCURRENTLY HEREWITH FOR THE
FOLLOWING SERIES:
NAME SEC FILE NO.
- ---- ------------
NUVEEN TAX-EXEMPT UNIT TRUST Series
- -----------------------------------
Series 691 33-49655
Series 693 33-49681
Series 695 33-49751
Series 697 33-49769
Series 698 33-49841
Series 699 33-49987
Series 700 33-50009
Series 701 33-50019
Series 702 33-50141
Series 703 33-50157
Series 704 33-50265
Series 705 33-50415
Series 706 33-50511
Series 707 33-50523
Series 708 33-50669
Series 709 33-50873
Series 710 33-50885
Series 711 33-51205
Series 712 33-51245
Series 713 33-51261
Series 714 33-51399
Series 715 33-51731
Series 716 33-51855
Series 717 33-51983
Series 718 33-52003
Series 719 33-52063
Series 720 33-52317
Series 721 33-52321
Series 722 33-52323
Series 723 33-52527
Series 724 33-52327
Series 725 33-53073
Series 726 33-53079
Series 727 33-53183
Series 728 33-53279
Series 729 33-53443
Series 730 33-53515
Series 731 33-53535
Series 732 33-53541
Series 733 33-53551
Series 734 33-53707
Series 735 33-53981
Series 736 33-53991
Series 737 33-54051
Series 738 33-54159
Series 739 33-54173
Series 740 33-54189
Series 741 33-54489
Series 742 33-54571
Series 743 33-54585
Series 744 33-54589
Series 745 33-54665
Series 746 33-54679
Series 747 33-54699
Series 748 33-54711
Series 749 33-54715
Series 750 33-55109
Series 751 33-55157
Series 752 33-55169
Series 753 33-55351
Series 754 33-55389
Series 755 33-55395
PAGE 2
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BASED UPON AN EXAMINATION AND MY KNOWLEDGE OF THE ACTIVITIES OF EACH OF
THE ABOVE LISTED SERIES, IT IS MY OPINION THAT THE UNITS THEREOF WERE
LEGALLY ISSUED, FULLY PAID AND NON-ASSESSABLE.
I CONSENT TO THE FILING OF THIS OPINION IN CONNECTION WITH THE RULE 24F-2
NOTICE FOR EACH SUCH SERIES FOR THE PERIOD ENDED SEPTEMBER 30, 1994.
VERY TRULY YOURS,
JOHN NUVEEN & CO. INCORPORATED
/S/JAMES J. WESOLOWSKI
JAMES J. WESOLOWSKI
GENERAL COUNSEL
