Historic Oregon City is the home of the third house ever built in the Oregon Territory, and Clackamas County's oldest house. The Ermatinger House was erected by one of Oregon's prominent citizens, Francis Ermatinger, a Portuguese native who was schooled in England and was a former Hudson's Bay employee. Ermatinger arrived in Portland in 1825, made his mark in Oregon retail and government, and erected this house circa 1843.
Some of the more significant landmarks include:
- Barclay House
- Ermatinger House
- Holmes House / Rose Farm
- McLoughlin House
- Mountain View Cemetery