Washington Township, Warren County, Ohio

Fort Ancient (33 WA 2) is a Native American earthworks complex located in Washington Township, Warren County, Ohio, along the eastern shore of the Little Miami River about seven miles (11 km) southeast of Lebanon on State Route 350. The site is the largest prehistoric hilltop enclosure in the United States with three and one-half miles (18,000 ft) of walls in a 100-acre (0.40 km2) complex. Built by the Hopewell culture, who lived in the area from the 200 BC to AD 400, the site is situated on a wooded bluff 270 feet (82 m) above the Little Miami. It is the namesake of a culture known as Fort Ancient who lived near the complex long after it was constructed. Maintained as a state historical park, the site was designated a National Historic Landmark for its significance. The State of Ohio purchased the land and made it Ohio's first state park in 1891. In addition, this is part of the Hopewell Ceremonial Earthworks, one of 14 sites nominated in January 2008 by the U.S. Department of the Interior for potential submission by the United States to the UNESCO World Heritage List. It was officially designated a World Heritage Site in September 2023 together with the earthworks at Hopewell Culture National Historical Park and the Newark Earthworks.

Gum Grove is a small unincorporated community in Warren County, in the U.S. state of Ohio.

Hammel and Millgrove are extinct towns in western Warren County, Ohio, United States. They are located along the Little Miami River, about 2 miles (3 km) south of Fort Ancient and 1 mile (1½ km) north of Roachester at the Strout Road crossing of the river. Hammel lies on the eastern shore of the river, in southwestern Washington Township, and Millgrove lies on the western shore of the river, in northeastern Salem Township. Hammel had its start in the 1840s when the railroad was extended to that point. The community was named after its founder. The GNIS considers Hammel to be a ghost town.

Cowen Run is a stream in the U.S. state of Ohio.Cowen Run was named in honor of a local family. A variant name was "Cowens Run".

The Crossed Keys Tavern, also known as the Cross Keys Tavern is a historic stone building located in Turtlecreek Township near Lebanon, Ohio. It is across the Little Miami River from the former Fort Ancient village. Built in 1802, it was operated as a tavern from 1809–1820.On October 21, 1976, it was added to the National Register of Historic Places.

Hicks is an unincorporated community in Warren County, in the U.S. state of Ohio.

Oregonia is an unincorporated community in northwestern Washington Township, Warren County, Ohio, United States, on the east shore of the Little Miami River about five miles northeast of Lebanon and six miles south of Waynesville. The ZIP Code for Oregonia is 45054.The first settlement there was around 1802, where there was a mill operated at various times by Nebo Gaunt, Ignatius Brown, and David Brown. Around 1820, it was known as Freeport. The Little Miami Railroad reached the village c. 1845. A post office called Oregon was established in 1846, and the name was changed to Oregonia in 1882. The post office has since been consolidated with the Lebanon post office. Today, Oregonia is a stop on the Little Miami Bike Trail which follows the former train route along the Little Miami River. Bikers, hikers, and canoers often stop at the market or a restaurant along the trail which follows the river on the former train route. In October of each year, the "Devils Staircase" motorcycle hill climb is held on a hill just south of the main settlement.

Middleboro is an unincorporated community in Warren County, in the U.S. state of Ohio.

Osceola is an unincorporated community in Warren County, in the U.S. state of Ohio.

Roachester is an unincorporated community in Warren County, Ohio, United States. Roachester is located at the junction of Ohio State Route 3 and Ohio State Route 123, 1.6 miles (2.6 km) east of Morrow.

Sugar Run is a stream in the U.S. state of Ohio. It is a tributary to Todd Fork. Sugar Run most likely was named for the sugar maple timber along its course. A variant name was "Sugar Creek".

Mathers Mill, alternately called Mathers Mills or Mather's Mills, is an unincorporated community in Warren County, Ohio, United States. It is approximately 5 miles east of Lebanon, and 2 miles south of Oregonia in eastern Turtlecreek Township. The area is served by the Oregonia post office, and Lebanon phone exchange and school district. Wilmington Road crosses the Little Miami River and intersects Corwin Road in this area. The bridge is known as the Mathers Mill bridge and the steep hill up out of the valley is sometimes referred to as Mathers Mill Hill. The area is named for a mill once owned by Richard Mather, which no longer exists. The settlement was a stop for the Little Miami Railroad. Mathers Mill is now a public access point with parking for the Little Miami Bike Trail, and canoe and fishing access point to the Little Miami River. A private canoe livery is located in the area on the east side of the river.