Main city: Waterloo
Timezone: Central
Phone type: Cell Number
Operator: United States Cellular Corp. - Iowa

Waterloo, a city in and the county seat of Black Hawk County, Iowa, United States. As of the 2010 United States Census the population decreased by 0.5% to 68,406; a recent 2011 Census estimates the population at 68,653, making it the sixth-largest city in the state. Waterloo is part of the Waterloo – Cedar Falls Metropolitan Statistical Area, and is the more populous of the two cities. ^source

Area code 319 is a telephone area code for southeastern and east-central Iowa. The 319 area code was one of the assignments of area codes in 1947, and originally covered Iowa's eastern third. (The map to the right is clickable; click on any of the area codes on the map to go to the area code for that region.) ^source