Cumberland County Population & Demographics Since the last census data, Cumberland County has seen an increase in population to approximately 243,764 in 2014, which has taken the county from a fourth class county to a third class county. Cumberland Valley offers a low-cost of living, access to large metropolitan lifestyles, and exceptional educational systems that provide for a highly functioning workforce. Cumberland County Population Year Population 1990 195,257 2000 213,674 2010 235,406 Change 2000-2010 +10.2% Largest Townships 2010 Census Township Population Hampden Township 28,044 East Pennsboro Township 20,228 Carlisle Borough (County Seat) 18,682 Upper Allen Township 18,059 Lower Allen Township 17,980 Silver Spring Township 13,657 Household Income 2010-2014 Households Amount Total Households 95,835 Less than $35,000 26% Between $35,000 & $75,000 34.3% Change 2000-2010 38.8% Median Household Income Year Amount 2000 $46,766 2010 $52,371 Median Age Year Age 2000 38.1 2014 40.7 Age Distribution 2011 Age Group 2000 2011 Under 25 32.6% 30.4% 25-44 28.5% 25.2% 45-64 24.1% 27.4% 65+ 14.8% 17%