William C. might have served in another state. According to the 1870 Pulaski County census, two of his children were born in Missouri, one in 1863 and another in 1866. I am fairly certain this is your relative. He appears as age 37 and born in Pennsylvania. His wife, Lucy, was also a native of Pennsylvania, born in 1845.

A few contributed trees list him as the son of Robert and Harriet Kelly Fulton, and he was born in Southwark, PA. I have not personally researched these trees.

The earliest record I found that places William C. in Pulaski County is an 1867 tax record. He died 21 FEB 1890, burial place unknown.

I think D.C. Fulton was definitely William’s uncle. Age 48 in 1861 would place his birth year in 1813, which certainly fits. He was in Company A, 6th AR INF, and as Mike pointed out, that company originated in Pulaski County. David Fulton also acquired several Pulaski County Land Patents between 1834 and 1842. He appears in the 1840 U.S. Census, Pulaski County, and in the 1850 U.S. Census, Pulaski County (age 39, b. PA), with his wife, Caroline (age 29, b. CONN) and daughter, Isabella, (age 1, b. AR). The 1860 U.S. Census clinches it. He listed his birthplace as Philadelphia.

According to contributed trees, David C. apparently returned to Pennsylvania after the war. He died in Philadelphia in 1870. The appearance of two of his children in the 1870 Philadelphia, PA, census helps to verify this.

I’m sorry I can’t give you anything more concrete on William C. Perhaps someone else can help here.