Putnam County was created in 1849. There are two conflicting stories as to the origin of the name: one possible source for the name name is in honor of Israel Putnam, who was a hero in the French and Indian War and a general in the American Revolutionary War. The other possibility is that it was named for Benjamin A. Putnam, an officer in the First Seminole War and a local Florida politician.
According to the U.S. Census Bureau, the county has a total area of 2,142 km² (827 mi²). 1,870 km² (722 mi²) of it is land and 273 km² (105 mi²) of it is water. The total area is 12.73% water.
As of the census2 of 2000, there are 70,423 people, 27,839 households, and 19,459 families residing in the county. The population density is 38/km² (98/mi²). There are 33,870 housing units at an average density of 18/km² (47/mi²). The racial makeup of the county is 77.91% White, 17.04% Black or African American, 0.42% Native American, 0.44% Asian, 0.04% Pacific Islander, 2.94% from other races, and 1.20% from two or more races. 5.92% of the population are Hispanic or Latino of any race.
There are 27,839 households out of which 28.10% have children under the age of 18 living with them, 52.80% are married couples living together, 12.90% have a female householder with no husband present, and 30.10% are non-families. 25.10% of all households are made up of individuals and 11.90% have someone living alone who is 65 years of age or older. The average household size is 2.48 and the average family size is 2.95.
In the county the population is spread out with 24.60% under the age of 18, 7.70% from 18 to 24, 24.20% from 25 to 44, 25.10% from 45 to 64, and 18.50% who are 65 years of age or older. The median age is 40 years. For every 100 females there are 97.60 males. For every 100 females age 18 and over, there are 94.20 males.
The median income for a household in the county is $28,180, and the median income for a family is $34,499. Males have a median income of $29,975 versus $20,955 for females. The per capita income for the county is $15,603. 20.90% of the population and 15.80% of families are below the poverty line. Out of the total people living in poverty, 30.60% are under the age of 18 and 13.10% are 65 or older.