M.M.White undertaker WashingtonDC Matthias M. White undertaker of Washington , DC Fisk and Raymond metallic coffins

Boyd's Washington and Georgetown directory : containing a business directory of Washington

 Taken up astray on the premises 457 Pa avenue night of Friday December - 1859 a dark black and white spotted sow, which the owner can have by calling on M.M. White and paying he charges and c. dec 14

White has moved in the Pennsylvania Avenue location and opened the new business and Fisk showroom.
It was a busy block and here are their new neighbors.

Residents 1850 Pennsylvania Avenue between 3rd and 4 ½ w. 

Beveridge, Mrs. boarding house, s side Pa av, btw 3 and 4 ½ w.
Beveridge, C. C., s side Pa av, btw 3 and 4 ½ w.
Brenner , Peter, fancy store, n side Pa av, btw 3 and 4 ½ w.

Browning, P. YV, tailor, n side Pa av, btw 3 and 4 ½ w.
Cattipliell, D. A., shoe store, n side Pa av, btw 3 and 4 ½ w.
Colonization Society, office n side Pa av, btw 3 and 4 ½ w.
Conrad, Christian, artist, s side Pa av, btw 3 and 4 ½ w.
Davis, John, painter, s side Pa av, btw 3 and 4 h w, 3d story.
Dickson, James, King’s hotel, n side Pa av, btw 3 and 4 ½ w
Duvall & Bro., merchant tailor, n side Pa av, btw 3 and 4 ½ w
Fitzgerald, James, tavern and fruit store, n side Pa av, b3 and 4 ½ w
Fowler, Samuel, tailor, n side Pa av, btw 3 and 4 ½ w
Gilbert, Nelson, boarding house, n side Pa av, btw 3 and 4 ½ w.
Globe, Daily, office Jackson Hall, n side Pa av, btw 3 and 4 ½ w
Gray, Richard, (col) barber, s side Pa av, btw 3 and 4 ½ w
Greason, Wm., fruit store and tavern, n side Pa av, btw 3 and 4? w.
House, s side Pa av, btw 3 and 4 ½ e
Hunt, Harvey W., math. inst. maker, s side Pa av, btw 3 and 4 ½ w
Hurdle, T. & A., painters, s side Pa av, btw 3 and 4 ½ w
Jackson Hall, (J. C. Rives,) n side Pa av, btw 3 and 4 ½ w.
Jordan, M., Potomac house, n side Pa av, btw 3 and 4| w.
King, P. H., hotel, n side Pa av, btw 3 and w.
Lee & Espey, cabinet makers, s side Pa av, btw 3 and 4| w.
McCarty, M., tailor, s side Pa av, btw 3 and 4b w.
McDermott, Michael, coach maker, s side Pa av, btw 3 and 4]- w.
Mann, Chas., n side Pa av, btw 3 and 44 w.
Metropolis House, n side Pa av, btw 3 and 4 h w.
Naylor, F., tin and copper smith, s side Pa av, btw 3 and 4 w.

Office of the German Spectator, s side Pa av, btw 3 and 4 h w.

Office Colonization Society, n side Pa av, btw 3 and 4| w.
Port Tobacco and Leonardtown stage office, Pa av, btw 3 and 4 ½ w. Reed, Jame3, (col) s side Pa av, btw 3 and 4 e.

Richards, J. H. T., shoe store, n side Pa av, btw 3 and 4b w.
Richards, J. H. D., shoemaker, n side Pa av, btw 3 3 and 4 ½ w.
Rowland, David, exchange office, n side Pa av, btw 3 and 4 ½ w.
Sinsheimer, L., clothing store, n side Pa av, btw 3 and 4 ½ w.
Stetson, Mrs., boarding house, s side Pa av, 3 and 4 ½ w.
Sage, G. A., printing office, s side Pa av, btw 3 and 4 ½ w.
Scott, Mrs., boarding house, s side Pa av, btw 3 and 4 ½ w.
Simms, E., & Son, gro. and wine store, s side Pa av, btw 3 & 4£ w.
Simms, Wm., ser. at King’s Hotel, n side Pa av, btw 3 and 4) w.
Semmes, T. F., wine store, n side Pa av, btw 3 and 4£ w.
Throop, J. V. N. , engraver, n side Pa av, btw 3 and 44 w.
Topham, G. W., Metropolis refectory, n side Pa av, btw 3 and 4 1/2 w
United States Hotel, E. S. Fuller, n side Pa av, btw 3 and 4] w.
Williams, F. H., refectory, n side Pa av, btw 3 and 4| w.
Yump, Francis, lodging house, n side Pa av, btw 3 and 4 ½ w. 

This is now the National Gallery 

What we know we know from the 2 census records that Ellen and the family appears in. Mathias doesn't not appear in any census but the 1840 and it does not provide any personal information. Not sure why Ellen didn't just enumerate the information about him in 1860. I can't find the entire family in the 1850 census and they'd been in DC since 1847 Emma born)