Avenue Grounds (I've not seen it called "The Avenue Grounds" though that seems like a more natural name) was the home of the first NL team in Cincinnati, who like today's team were called the
Reds. This team followed the Cincinnati Red Stockings in the Queen City, and had a couple of players in common with that team, but did not play at the Red Stockings' home. Instead they played at this park near the edge of town for their relatively short and mostly unhappy tenure in the league. After disbanding in 1879, the park was used for amateur games for the next 15 or so years while major-league teams in Cincinnati played their games at the
Bank Street Grounds.
Google Drive Link for Avenue Grounds
We have come rather a way compared to parks early in the thread in terms of information available. I haven't found any atlases or maps that show the structures for the park, but there does seem to be one sketch that I'm assuming is contemporary and that guided my modeling. I didn't find any dimensions,
but did find an article that claimed the right field line was short and center field and left field were big, so I tried to reflect that. The background is from the right part of Cincinnati, but retains a bit more of the modern aspects than I'd prefer. Still, since according to the Wikipedia article they're not even quite 100% sure where the ballpark is I'll take this as being as close as I can get it...
Enjoy!