When was Sullivan County founded?

Sullivan County was founded in 1817, formed from Knox County, and named after Daniel Sullivan.

What is the county seat of Sullivan County?

The county seat of Sullivan County is Sullivan.

Is there an online parcel map for Sullivan County?

Yes. Indiana Geographic Information Office (IndianaMap) publishes a parcel map of 18,585 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.

Has Sullivan County's boundary or name changed?

Sullivan County was created in 1817 from Knox County. Since then the Atlas of Historical County Boundaries records 6 later changes, chiefly involving Vigo County, Clay County and Greene County.

Is my lot in a flood zone?

We do not have flood maps for Sullivan County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Sullivan County, Indiana: parcels, history and offices

Where it is

Sullivan on the map of Indiana

Indiana has 92 counties and county equivalents, each with its own records office. Shapes with a page are links.

Counties of Indiana · Sullivan highlighted

History

Formed in 1817 from Knox County

An old deed may name a county that no longer exists, or a boundary that has since moved.

Sullivan County was created from Knox County on January 15, 1817. It was named after Daniel Sullivan. Between 1818 and 1825, Sullivan County lost territory to the creation of Vigo, Owen, Greene, and Clay counties, though it gained a small area back from Knox County in 1842.

Boundary changes from the Newberry Library, Atlas of Historical County Boundaries; the 5 that matter most are shown first.

1817
Sullivan County created Sullivan created from Knox.
from Knox
15 January 1817 · Ind. Acts 1816, 1st sess., ch. 49, secs. 1-2, 5/pp. 205, 207
1818
Lost territory Sullivan lost to creation of Vigo.
to Vigo
15 February 1818 · Ind. Acts 1817, 2d sess., spec., ch. 14, secs. 1-2/p. 34
1819
Lost territory Sullivan lost to creation of Owen.
to Owen
1 January 1819 · Ind. Acts 1818, 3d sess., ch. 26, secs. 1-2/p. 96
1819
Lost territory Sullivan lost to Vigo.
to Vigo
10 January 1819 · Ind. Acts 1818, 3d sess., ch. 29/p. 107
1821
Lost territory Sullivan lost to creation of Greene.
to Greene
5 February 1821 · Ind. Acts 1820, 5th sess., ch. 49, secs. 1-2, 8/pp. 114, 117

Show all 9 changes (4 more, mostly small adjustments)

1817
Sullivan County created Sullivan created from Knox.
from Knox
15 January 1817 · Ind. Acts 1816, 1st sess., ch. 49, secs. 1-2, 5/pp. 205, 207
1818
Lost territory Sullivan lost to creation of Vigo.
to Vigo
15 February 1818 · Ind. Acts 1817, 2d sess., spec., ch. 14, secs. 1-2/p. 34
1819
Lost territory Sullivan lost to creation of Owen.
to Owen
1 January 1819 · Ind. Acts 1818, 3d sess., ch. 26, secs. 1-2/p. 96
1819
Lost territory Sullivan lost to Vigo.
to Vigo
10 January 1819 · Ind. Acts 1818, 3d sess., ch. 29/p. 107
1821
Lost territory Sullivan lost to creation of Greene.
to Greene
5 February 1821 · Ind. Acts 1820, 5th sess., ch. 49, secs. 1-2, 8/pp. 114, 117
1825
Lost territory Sullivan lost to creation of Clay.
to Clay
1 April 1825 · Ind. Acts 1825, 9th sess., ch. 15/p. 17
1842
Gained territory Sullivan gained small area from Knox.
from Knox
5 December 1842 · Ind. Rev. Stat. 1843, ch. 2, secs. 2, 26, 28-31, 36-37, 42-44, 61, 67, 77, 80-82, 85-86/pp. 68, 74-81, 84, 86, 88-89
1852
Boundary clarified Sullivan boundaries were redefined; mistake in description corrected 5 March 1859 (no change).
no change
7 June 1852 · Ind. Rev. Stat. 1852, 1:ch. 14, secs. 23, 27, 31, 78, 86/pp. 174, 176-177, 192, 194
1859
Boundary clarified Sullivan boundaries were redefined, correcting mistake of 7 June 1852 (no change).
no change
5 March 1859 · Ind. Acts 1859, 40th sess., ch. 12/p. 43

Land and parcels

What the maps cover in Sullivan

Who publishes each layer, how good it is, and when we last checked.

Parcels Good enough

Lot lines and tax-map numbers for 18,585 parcels from Indiana Geographic Information Office (IndianaMap). Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
edited 6 October 2026 · checked 15 October 2026
Address points Official

One point per address, 11,939 in all from Indiana Geographic Information Office (IGIO).
edited 8 March 2026 · checked 13 October 2026
Buildings Reference

Roof outlines traced from aerial imagery from FEMA Response Geospatial Office with Oak Ridge National Laboratory (ORNL). Good for seeing what is on a lot; not accurate enough to set a fence from.
checked 18 October 2026

Official: from the office that keeps the record
Good enough: a reliable statewide or national copy
Fallback: a guide only; check the official record
Missing: nothing public found yet

People and land

Sullivan by the Census

Population

20,817 2020 Census count

Housing units

8,788 2020 Census count

Land area

447 square miles

Water area

6.9 square miles

People per sq mi

47 population ÷ land area

Source: US Census Bureau, 2020 Census; US Census Bureau, 2020 Gazetteer Files. Not endorsed or certified by the Census Bureau.

Rules and offices

Sullivan County's official site

We have found the county's site but not its offices yet; start there.

County government

County government
The official website of Sullivan County.
sullivancountyindiana.us

See your own lot on these maps

Open Sullivan County on Parcel Chart's free map and click your parcel. Save it with a free account; the full record of your place (site map, projects, documents) is Pro, in early access.

Open the free map no sign-in Pro early access

Questions

Common questions about Sullivan County

When was Sullivan County founded?: Sullivan County was founded in 1817, formed from Knox County, and named after Daniel Sullivan.
What is the county seat of Sullivan County?: The county seat of Sullivan County is Sullivan.
Is there an online parcel map for Sullivan County?: Yes. Indiana Geographic Information Office (IndianaMap) publishes a parcel map of 18,585 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has Sullivan County's boundary or name changed?: Sullivan County was created in 1817 from Knox County. Since then the Atlas of Historical County Boundaries records 6 later changes, chiefly involving Vigo County, Clay County and Greene County.
Is my lot in a flood zone?: We do not have flood maps for Sullivan County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby

Sullivan CountyIndiana