The terrain of Hamlin County consists of low rolling hills, dotted with small lakes and ponds. The land is largely dedicated to agriculture. The terrain slopes to the south-southeast, and its highest point is on the eastern boundary line, near its NE corner, at 1,949' ASL. Hamlin County has a total area of, of which is land and is water.
As of the 2000 United States Census, there were 5,540 people, 2,048 households, and 1,452 families in the county. The population density was 11 people per square mile. There were 2,626 housing units at an average density of 5 per square mile. The racial makeup of the county was 98.48% White, 0.13% Black or African American, 0.58% Native American, 0.18% Asian, 0.11% from other races, and 0.52% from two or more races. 0.63% of the population were Hispanic or Latino of any race. 28.7% were of German, 21.8% Norwegian, 13.0% Finnish and 7.6% American ancestry, 95.2% spoke English, 2.6% German and 1.5% Spanish as their first language. There were 2,048 households out of which 33.80% had children under the age of 18 living with them, 63.50% were married couplesliving together, 4.80% had a female householder with no husband present, and 29.10% were non-families. 27.00% of all households were made up of individuals and 14.50% had someone living alone who was 65 years of age or older. The average household size was 2.62 and the average family size was 3.22. The county population contained 29.40% under the age of 18, 6.90% from 18 to 24, 24.00% from 25 to 44, 20.50% from 45 to 64, and 19.20% who were 65 years of age or older. The median age was 38 years. For every 100 females, there were 98.90 males. For every 100 females age 18 and over, there were 96.80 males. The median income for a household in the county was $33,851, and the median income for a family was $41,511. Males had a median income of $28,446 versus $21,412 for females. The per capita income for the county was $16,982. About 7.20% of families and 12.10% of the population were below the poverty line, including 17.00% of those under age 18 and 14.30% of those age 65 or over.
2010 census
As of the 2010 United States Census, there were 5,903 people, 2,108 households, and 1,483 families in the county. The population density was. There were 2,760 housing units at an average density of. The racial makeup of the county was 96.7% white, 0.3% American Indian, 0.2% black or African American, 0.2% Asian, 1.8% from other races, and 0.8% from two or more races. Those of Hispanic or Latino origin made up 2.5% of the population. In terms of ancestry, 42.3% were German, 24.0% were Norwegian, 7.0% were English, 6.1% were Irish, 5.4% were Dutch, and 5.3% were American. Of the 2,108 households, 33.2% had children under the age of 18 living with them, 61.4% were married couples living together, 5.6% had a female householder with no husband present, 29.6% were non-families, and 25.6% of all households were made up of individuals. The average household size was 2.68 and the average family size was 3.28. The median age was 36.8 years. The median income for a household in the county was $44,439 and the median income for a family was $54,483. Males had a median income of $36,921 versus $24,645 for females. The per capita income for the county was $21,558. About 4.9% of families and 7.5% of the population were below the poverty line, including 11.5% of those under age 18 and 7.9% of those age 65 or over.
