County was established in 1885 from a portion of Wasco County
and was named after Col. Cornelius Gilliam, a veteran of the
Cayuse Indian War. The first county seat was at Alkali, now
Arlington. At the general election of 1890, voters chose to
move the county seat to Condon, known to early settlers as "Summit
Springs." A brick courthouse was built in Condon in 1903
but was destroyed by fire in 1954. The present courthouse, built
on the same site, was constructed in 1955.
County is in the heart of the Columbia Plateau wheat area. The
economy is based mainly on agriculture, with an average farm
size of about 4,200 acres. Wheat, barley and beef cattle are
the principal crops. The largest individual employers in the
county are two subsidiaries of Waste Management Inc., Chemical
Waste Management of the Northwest and Oregon Waste Systems,
Inc., two regional state-of-the-art waste disposal landfills.
elevations of over 3,000 feet near Condon in the south of the
county and 285 feet at Arlington, 38 miles north, the county
offers a variety of climates and atmosphere. Hunting, fishing
and tourism are secondary industries. Two major rivers, the
John Day and Columbia, traverse the area east-to-west, as well
as Interstate 84. Highway 19 connects the county's major cities
north-to-south and serves as gateway to the John Day Valley.