Palmyra, Edwards County, Illinois - Wikipedia Entries on Waymarking.com

County of marker: Wabash County
Location of marker: IL-1 & CR-1690N Blvd., turnout 3½ N. Mt. Carmel
Erected by: Mount Carmel Chapter, Daughters of the American Revolution

Marker Text:
This tablet marks the site of Palmyra, the first county seat of Edwards County, settled April 22, 1815. Edwards County at that time embraced one third of the State of Illinois and a part of Michigan and Wisconsin, extending to upper Canada. Twenty Indian mounds were also located on this site.

Further Info about the county after Palmyra, from Wikipedia:
Albion was founded in 1816 by a colony of Englishmen led by George Flower. The American settlers in Edwards County, many of them veterans of the War of 1812, mostly from Kentucky, viewed the English colony with great suspicion.

Flower came to America in 1816. He and Morris Birkbeck, another Englishman, met and agreed to explore the western country with the idea of starting a colony of their own countrymen. After a long journey through Ohio, Indiana, and the Illinois Territory, they were so impressed with the beauty of the countryside around Boultinghouse Prairie that they knew they had found what they were looking for. They bought all the land they could afford, and eventually brought over from England more than 200 settlers, £100,000 in capital, and a carefully thought out selection of livestock and agricultural implements. The area became known as the English Settlement.

In 1824, the county seat of Edwards County was moved from Palmyra to Albion. Residents of Mount Carmel felt the county seat should be in Mount Carmel and not Albion. Four companies of militia marched from Mount Carmel toward Albion to seize the county documents stored in the courthouse. The situation was resolved by separating Wabash County from Edwards County at the Bon Pas Creek in 1824. The divided counties remain two of the smallest in Illinois.