I was able to visit the Chesterfield Historical Society years ago, when it was still in the Court House. They have an informative site at
http://chesterfieldhistory.com/........ That site has a photo of Magnolia Grange, which is a lovely house, and "the only historic home open to the public in Chesterfield County, depicting early 19th century life." Magnolia Grange and the rest of Chester are well worth a visit from anyone with connections in Chesterfield County or an interest in history. ............
Unfortunately, your Cogbill/Cheatham/Terrell/Nunn family tree is accessible only to people with an Ancestry membership. I will gladly take a look if I ever become a member again. I do not have any COGBILLs in my direct ancestry, but they were an important family with many connections to other Chesterfield County families. For example, I am very slightly related to Joseph Beverly Vaden, who married Susan "Sue" E. Cogbill. ..............
Best, Laura