In 1840 the population was 809, and 1,087 in 1850.
In 1846 Henry Howe first visited Middletown. He wrote, in part, this description of the town of that time.
Middletown is twelve miles northeast of Hamilton, and twenty below Dayton, in a rich and beautiful country. The Miami canal runs east of the central part of the town, and the Miami river bounds it on the west. It is connected with Dayton and Cincinnati and with West Alexandria, in Preble county, by turnpikes. The Warren county canal enters the main canal at this town. Two or three miles above, a dam is thrown across the Miami, from which a connecting feeder supplies the Miami canal. This work furnishes much water power, which, with a little expense, can be increased and used to a great advantage. There are within three miles of Middletown eight flouring mills on the river and canal." . . . It contains . . . 16 mercantile stores, 2 forwarding houses, 1 grist mill and 1 woolen factory . . .
Source: The Economic Development of Middletown, Ohio 1796-1865 by George C. Crout