Hillforest, also historically known as Forest Hill, is an outstanding and architecturally unique Italianate villa located on a hillside overlooking the Ohio River in Aurora, Indiana. Built between 1852 and 1855, the grand mansion was designed by the renowned architect Isaiah Rogers for prominent local industrialist Thomas Gaff. The residence is a premier example of "Steamboat Gothic" architecture, featuring a design that directly reflects Gaff's involvement in the shipping and steamboat industries. Its striking exterior is characterized by a circular, two-story front portico, delicate bracketed cornices, and a prominent central cupola reminiscent of a steamboat's pilot house. Inside, the home boasts a magnificent free-standing flying staircase, elegant plaster moldings, and arched doorways, all of which contribute to its designation as a National Historic Landmark.

Historically, the estate is highly significant for its association with Thomas Gaff, a leading 19th-century entrepreneur whose diverse business ventures spearheaded the economic development of Aurora and the Ohio River Valley. Alongside his brother James, Gaff established successful enterprises in distilling, brewing, farming, commercial shipping, and banking, positioning himself as one of the region's most influential citizens. Hillforest served as the opulent centerpiece of Gaff's estate and stood as a physical testament to his wealth and civic stature during the peak of the riverboat era. Saved from demolition and meticulously preserved by the Hillforest Historical Foundation since 1956, the mansion survives today as a vital monument to the region's mid-19th-century industrial and maritime heritage.

The Jennison Guard Site, designated archaeologically as 12D29, is a premier prehistoric archaeological site located near the confluence of the Great Miami and Ohio Rivers in Dearborn County, Indiana. Listed on the National Register of Historic Places in 1975, the site represents a major, well-preserved village of the Fort Ancient culture, dating primarily to the late prehistoric period between approximately A.D. 1000 and 1300. Because it was buried under thick layers of alluvial silt deposited by seasonal flooding, the site was shielded from the destructive effects of modern agriculture and looting. This exceptional preservation makes the Jennison Guard Site one of the most significant and intact examples of a Fort Ancient settlement in the middle Ohio River Valley.

Archaeological investigations at the site have yielded a wealth of information regarding prehistoric Native American life, revealing a classic circular village layout complete with a central plaza, surrounding residential zones, and domestic refuse middens. Excavations have uncovered postmold patterns delineating rectangular wall-trench houses, deep storage pits, and hearths, alongside an abundant assemblage of diagnostic pottery, shell hoes, triangular stone projectile points, and bone tools. The exceptional preservation of organic remains, including faunal bones and carbonized plant seeds, has provided researchers with invaluable data to reconstruct the subsistence strategies, agricultural practices, social organization, and regional trade networks of the region's late prehistoric inhabitants.