Portland’s scenic Skyline Boulevard weaves in and out of the forested West Hills, making it a favorite of bikers, runners, and Sunday drivers. With so much natural beauty, many visitors completely miss the sign and winding narrow path leading to an unassuming survey marker that is the ultimate definition of property lines in all of Oregon and Washington since 1851.

As part of the 1803 Louisiana Purchase, the United States established the Oregon Territory in 1848 after agreeing on the 49th parallel border with Great Britain. Not surprisingly, the territorial government quickly realized the need for adjudicating property claims among settlers.

Enter John B. Preston, the first Surveyor-General of the Oregon Territory, charged by the U.S. General Land Office to establish the primary survey reference—the Initial Point—for the Oregon Territory. The survey had several challenges. The territory spanned east-west from the Snake River to the Pacific, and north-south from the 49th parallel to the California border.

Preston’s team had to avoid putting their north-south meridian and east-west baseline through major bodies of water and geographic features. The work has since stood the test of time, avoiding early surveyor faux pas, such as the one that unwittingly established the isolated U.S. enclave of Point Roberts, Washington. Ironically, this was a result of the earlier agreement with Britain in establishing the 49th parallel border that precipitated the Oregon Territory.

Willamette Stone Heritage Park is easily accessible if you know where to look on winding Skyline Boulevard. A macadam path leads to the stone itself and interpretive plaques in a deep, forested hollow. The heavy forestation makes this a somewhat curious spot for surveyors to establish a critical benchmark, although the sightlines of 1851 were likely different than those today. Three donated benches surround the stone. Visitors can sit and contemplate the enormous significance the stone has for Oregon and Washington homeowners seeking property easements from their local planning boards. The setting is at once bucolic, quiet, and contains a faint air of mystery.