When the Oregon Territorial Legislature created Wasco County on January 11, 1854, it wasn’t just any county. It was one of the largest in the country at 130,000 square miles. I know what you’re thinking: “How is that possible? The whole state of Oregon only encompasses 98,386 square miles!” Well you see the Oregon Territory was huge, extending up into what is now Canada, south to California, and east to the Rocky Mountains. Wasco County, in 1854, made up a big chunk of that, extending from the Washington border to the California border, and stretching east from the Cascades to the Rockies.
Eventually seventeen other eastern Oregon counties and big chunks of several states were carved out of Wasco County, which now covers a mere 2,387 square miles (still bigger than Rhode Island or Delaware). Its northern border is still the Columbia river, but now heading east it ends at the Deschutes. The Warm Springs Indian Reservation makes up the southern border, with Mt. Hood National Forest the western. One thing that hasn’t changed? The Dalles has been the county seat the whole time (though it used to be called Dalles City).