The location of the obelisk is now indicated by a stainless steel marker in Willamette Stone State Heritage Site, an Oregon state park approximately four miles west of downtown Portland. The site is near Skyline Boulevard, in the West Hills overlooking the Tualatin Valley and the Willamette River watershed. The grid defined by the stone extended the Public Land Survey System and was used as the basis of land claims in the Oregon Territory. The first marker, a red cedar stake, was placed on the site on June 4, 1851, by John B. Preston, the first Surveyor General of the Oregon Territory. Preston was appointed by President Millard Fillmore to create a system for surveying land in the territory; he lost his position in 1853, and "drifted into obscurity." The location was chosen such that the baseline would not cross the Columbia River and the meridian would lie west of Vancouver Lake. The meridian and baseline were surveyed using solar compasses by James E. Freeman of Wisconsin and William Ives of Michigan. Ives surveyed the baseline in both directions and the meridian to the north; Freeman surveyed the meridian to the south. The grid system was an extension of the system used in the Northwest Territory proposed by Thomas Jefferson. The Willamette Stone marked the location of the first townships and ranges north and south of the marker. The Department of Interior replaced the stake with a stone obelisk on July 25, 1885. On two sides, the stone was marked with the words "BASE" and "LINE", while on the other two sides it was marked with the words "WILL." and "MER." As the stone was vandalized in the 1980s, the federal government replaced it with the current marker, and an accompanying bronze plaque:
Beginning here, the Willamette meridian was established running north to Puget Sound and south to the California border, and the baseline was established running east to the Idaho border and west to the Pacific Ocean.
Streets
The location of the Willamette meridian and Willamette baseline can be identified by various streets that follow or parallel their courses, often named to call attention to this fact.
In Lewis County, Washington, east of Toledo, Templeton and Schmidt roads follow the meridian for the mile adjacent to SR 505. South of US Highway 12 at Ethel, Tucker and Classe Roads follow the meridian for about 3 miles.
In Thurston County, Washington, east of Lacey, Tucker Road SE follows the meridian for about 3/4 of a mile.
In Kitsap County, Washington, east of Bangor, parts of Lester Road NW, Grampus Road, and Snook Road follow the meridian for a total of about two miles.
In Newberg, Meridian Street is several miles west of the Willamette meridian.
East–West streets and the baseline
;Streets named because they follow the baseline
Baseline Road in Tillamook, Washington, Hood River, Gilliam, and Morrow counties all follow or start at the Willamette baseline.
;Other streets that follow the baseline
Stark Street in east Portland and Washington County follows the Willamette baseline.
;Streets named because they parallel the baseline
Division Street in Portland and Section Line Road in East Multnomah County follow the division between the first and second rows of square-mile sections south of the Willamette baseline.
