the description in the constitution which follows the expression "up the middle of the widest channel thereof" to these words:
to a point near Fort Walla-Walla, where the forty-sixth parallel of north latitude crosses said river; thence east on said parallel to the middle of the main channel of the Shoshones or Snake River; thence up the middle of main channel of said river, to the mouth of the Owyhee River; thence due south, to the parallel of latitude forty-two degrees north; thence west, along said parallel, to the place of beginning …
This change was made in order to make the north boundary of Oregon conform to the act of congress which organized Washington Territory in 1853. The debates in the constitutional convention indicate that that body wrote the original clause about the north boundary in conflict with the act creating Washington Territory because they considered the Snake River boundary "not only natural in itself, but natural in uniting the political destinies and social feelings of a people residing in the same valley," that is, the Walla Walla valley. However, congress adopted the 46th parallel instead of the river.
The Oregon-Washington boundary on the 46th parallel, between Snake and Columbia rivers, was surveyed and marked in 1863-64 under the direction of the United States general land office. The latitude used was derived from more than 500 observations with the sextant. Two observation stations were occupied, one near the foot of Cathedral Rock on the Columbia River, the other near Cottonwood Creek on the west side of the Blue Mountains. A random line was run between them, which showed an apparent difference of latitude of 4 seconds, or about 400 feet. The final line was run on the mean latitude. Marks were set at mile intervals for 42 miles east from the Columbia River, then at irregular intervals over the Blue Mountains. The measured length of the line was 96 miles 57 chains. The easternmost mark, which was placed 3 chains from the west bank of Snake River was a 7½-foot post 12 inches in diameter, marked "W" on the north, "O" on the south, and "46 L 1868" on the east side, and set in a 6-foot pile of stones.
The boundary line between Oregon and California was established in 1868-69. To determine the proper position for the northeast corner of California (latitude 42 degrees, longitude 120 degrees) an astronomic station was established at Camp
