Mercer County, New Jersey

Founding: 1838
Parent counties: Burlington, Hunterdon, and Middlesex

Namesake: Hugh Mercer, Continental Army general
Seat: Trenton (1838–)

Land area: 225 square miles

Population (2020): 387,340

Population (historic): 21,502 (1840); 37,419 (1860); 58,061 (1880); 95,365 (1900); 187,143 (1930)

Periods of population growth: pre-1840–2020

Subdivisions: One city; four boroughs; nine CDPs; seven townships

Pre-1940 residences (estimated): 34,897 (24.2%)
Pre-1940 housing survival rate: 63%
Pre-1860 housing survival rate (1940): 40%

Farm housing in disrepair (1950): 9.9%

Nonfarm housing in disrepair (1950): 4.9%

Average farmhouse value (1930): $3,695
Average outbuilding value (1930): $2,608
Average farmhouse size (1940): 7 rooms
Number of farms (1920): 1,330
Average farm size (1920): 66.5 acres
_________________________________________________________________________________

Trenton

Namesake: William Trent, Philadelphia merchant

Founding: 1719 (platting); 1792 (incorporation)

Population (2020): 90,871

Population (historic): 1,946 (1790); 3,925 (1830); 17,228 (1860); 57,458 (1890); 123,356 (1930)

Periods of population growth: pre-1790–1820; 1830–1950; 2010s
Pre-1940 residences (estimated): 20,686 (59.7%)
_________________________________________________________________________________

View and filter the data. Or see a map.

_________________________________________________________________________________