Notes:
John, being the illegitimate son of Susanna is speculative, but everything fits. The 1930 census indicates that he was married twice (1st at age 23) and 2nd to Margaret A. Sanders (her first marriage) They can be found in the 1900-1930 census of District 11, Baltimore Co., MD
1870 Census, MD, Baltimore Co., 11th Dist. page 671 & 672, 19 Aug 1870
Enos Mumma, 53, Laborer, $300 real estate, b. PA
Susan, 41, keeps house, b. PA
Susan, 20, b. PA
George, 14, b. MD
Lizzie, 12, b. MD
Lina, 9, b. MD
Johnny Binder, 1, b. MD
1880 Census MD, Baltimore Co., District 10, page 365
Enos Mumma, age 62, b. PA, father b. PA, mother b. PA
Susanna Mumma age 59, b. PA, father b. Germany, mother b. Ireland
John Mumma, 10, grandson, b. MD, father, MD, mother PA
1900 Census MD, Baltimore Co., District 11, ED 48, dwelling #116
Mumma, John, head, July 1869, 30, m: 2 yrs., b: MD/PA/PA, day laborer
" , Margaret A., wife, Jul 1857, 42, m: 2 yrs., b: Germany/Germany/Germany, immigrated 1867
Sandner, George S., boarder, Nov 1855, 44, single, b: Germany/Germany/Germany, immigrated 1867
1910 Census, MD, Baltimore, District 11, ED 38, dwelling 185
Mumma, John, head, 40, m2 13 yrs, b: MD/PA/PA, laundry
" , Margaret A., wife, 52, m1, 13 yrs, b: Germany/Germany/Germany, immigrated 1867
Sandner, George S., brother-in-law, 54, single, b: Germany/Germany/Germany, immigrated 1867, laundry
1920 Census, MD, Baltimore, District 11, ED 38, dwelling 212, Long Green Road
Mumma, John, head, owns, 50, b: MD/USA/PA, carpenter, house work
" , Margaret A., wife, 62, immigrated 1867, b: Germany/Germany/Germany
Sanders, George S., brother-in-law, 64, single, immigrated 1867, b: Germany/Germany/Germany
1930 Census, MD, Baltimore, District 11, ED 50, dwelling 85, Long Green Piike
Mumma, John F., head, owns, $4000, has radio, 60, 1st m: @ age 23, b: MD/MD/MD, carpenter, contractor
" , Margaret A., wife, 72, 1st m: @ age 39, b: Germany/Germany/Germany, immigrated 1867
Sanders, George S., brother-in-law, 74, single, b: Germany/Germany/Germany, immigrated 1867
John's aunts Catherine Guyton and Elizabeth Eisholtz are living 2 doors away.