U.S. SECURITIES AND EXCHANGE COMMISSION
                        Washington, D.C.  20549

                              FORM 24F-2
                    Annual Notice of Securities Sold
                        Pursuant to Rule 24f-2


1.  Name and address of issuer:  BlackRock Municipal Bond Fund, Inc.
                                 100 Bellevue Parkway
                                 Wilmington, DE  19809

2.  Name of each series or class of securities for which this Form is filed
    (If the Form is being filed for all series and classes of securities of
    the issuer, check the box but do not list series or classes):  [ X ]

3.  Investment Company Act File Number: 811-02688

    Securities Act File Number:  333-57634

4.  (a)  Last day of fiscal year for which this Form is filed: 6/30/2020

    (b)  Check box if this Form is being filed late (i.e., more than 90
    calendar days after the end of the Issuer's fiscal year).   [     ]

    (c)  Check box if this is the last time the issuer will be filing
    this form.   [     ]

5.  Calculation of registration fee:

    (i) Aggregate sale price of securities sold during
    the fiscal year pursuant to section 24(f):            $ 6,852,117,815

    (ii) Aggregate price of securities
    redeemed or repurchased during the
    fiscal year:                             $ 4,443,794,260

    (iii) Aggregate price of securities
    redeemed or repurchased during any
    prior fiscal year ending no earlier
    than October 11, 1995 that were not
    previously used to reduce registration
    fees payable to the Commission:          $ 0

    (iv) Total available redemption credits [add
    items 5(ii) and 5(iii):                             - $ 4,443,794,260

    (v) Net sales - if item 5(i) is greater than
    Item 5(iv) [subtract Item 5(iv) from Item(i)]:        $ 2,408,323,555

    (vi) Redemption credits available for
    use in future years - if Item 5(i) is
    less than Item 5(iv) [subtract Item
    5(iv) from Item 5(i)]:                   $ (0)

    (vii) Multiplier for determining registration fee:    x .0001298

    (viii) Registration fee due [multiply Item 5(v) by
    Item 5(vii)]:                                         $ 312,600.00

6.  Prepaid Shares

    If the response to item 5(i) was determined by deducting an amount of
    securities that were registered under the Securities Act of 1933
    pursuant to rule 24e-2 as in effect before October 11, 1997, then
    report the amount of securities (number of shares or other units)
    deducted here: 0  If there is a number of shares or other
    units that were registered pursuant to rule 24e-2 remaining unsold
    at the end of the fiscal year for which this form is filed that are
    available for use by the issuer in future fiscal years, than state
    that number here: 0.

7.  Interest due - if this Form is being filed more than 90 days after
    the end of the issuer's fiscal year:

                                                          $ 0

8.  Total of the amount of the registration fee due plus any interest due
    [line 5(viii) plus line 7]:

                                                          $ 312,600.00

9.  Date the registration fee and any interest payment was sent to the
    Commission's lockbox depository:

    Method of Delivery:

    [X]   Wire Transfer
    [ ]   Mail or other means


SIGNATURES

This report has been signed below by the following persons on behalf of the
issuer and in the capacities and on the dates indicated.


By:     /s/Scott Hilton
        Scott Hilton
        Assistant Treasurer

Date:   9/16/2020