The USGS Geographic Names Information System (GNIS) is a good way to locate things like cemeteries and populated places. As an example, John Hunt was born near Downey, Iowa. A search of GNIS shows a historical town of Downey and a historical post office in Downey. Clicking the GNIS in Google maps shows Downey is a small unincorporated village in Springdale township, Cedar County, Iowa. A Zip+4 search shows that Downey is no longer a valid zip code, to use West Branch, IA instead.
An interesting point is that Downey is less than a mile east of the Cedar / Johnson County line. This researcher lists Johnson County, near Downey, Iowa as John's birthplace citing a family Bible. Looking at the 1870 US Census for Cedar County, Springdale township, the Samuel Hunt family was living there 20 August 1870, listing John Hunt as 10 months old. So, apparently they were living in Cedar County, but John was born in Johnson County. I'm not sure what the county the birth certificate lists.
Census extract for the 1870 census after the jump.
Series: M593 Roll: 380 Page: 353
Page No. 29
Schedule 1. Inhabitants in Springdale Township, in the County of Cedar, State of Iowa, enumerated by me on the 20th day of August, 1870.
Post office: Tipton (signed by what appears to read:)Henry (Harry?) Reigart, Ass't Marshal. Stamped with the number 353, which is the microfilm roll page number.
Dwelling 240, Family 248
Hunt, Samuel, Age 36, Male, White, Farmer, $1,000 real estate, $840 personal estate, born in Ohio, Male citizen of the US over age 21.
Hunt, Sarah, Age 28, Female, White, Keeping House, born in Pennsylvania
Hunt, Charles, Age 11, Male, White, born in Ohio, Attending school
Hunt, John, Age 8/12, White, born in Iowa, Born in the last year in the month of December.
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