Overview

Sullivan County, IN (shown in white) has 447.2 mi² of land area and 6.92 mi² of water resources. The county is bordered by:

• Clark County, IL
• Clay County, IN
• Crawford County, IL
• Greene County, IN
• Knox County, IN
• Vigo County, IN

The county's elevations range from a low of 410.1' to a high of 649.6', with a weighted average of 510' above sea level.

Temperatures range from average lows around 21°F to average highs around 87.5°F. A year-round daily temperature averages 55°F. Average annual precipation is 48.6". With these temperatures and precipation, the majority of the county scores as an 6A using the USDA Plant Hardiness Zone Map (the standard by which gardeners and growers can determine which perennial plants are most likely to thrive in a location).

The estimated population of Sullivan County is 20,800 with 7,725 households. These households are spread across 13 unique municipalties (not all shown).