That would be Multnomah county, though smallest in area of the 36 Oregon counties, it is the most populous as its county seat, Portland, is the state's largest city. In 2010, the county had a population of 735,334.
Tyrrell County is the smallest by population. The population of the county is 4.247.
Pickett County. The population was 4,945. It has the smallest population of any county in Tennessee according to the 2000 census
McCormick County is the county with the smallest population. The county has a total area of 394 square miles. The population is approximately 9960 residents.
The smallest county by population in Wyoming is Niobrara County with 2,484 people (2010 US Census).
According to census.gov, Multnomah County, Oregon, has the most population at 701,986 people in 2007.
Smallest county population wise in Ireland is Leitrim 27-28 thousand.
According to census.gov, the 2007 population estimate for Harney County, Oregon is 6,767.
Robertson County
32567
The population of Linn County at the time of the 2010 census was 116,672.
Clark County is Idaho's smallest county based on population with a population of 982 as of the 2010 Census. Payette County is Idaho's smallest county based on area with 408 square miles.