The result of all of that earth moving is a landscape rich in diversity. Towering peaks comprised largely of granite are visible in the distance from many vantage points along the Grande Tour route. Millions of years ago, large blocks of rock gradually folded and slid into the earth, leaving ragged cliffs of Columbia River Basalt standing above the valley. Now colorfully covered with lichen, the cliffs guard the many creeks and rivers that tumble from mountain top to valley floor and eventually to the Columbia River and Pacific Ocean. Glacial rock, ground into loess and carried to the valley floor by wind and water, makes up much of the rich soil that is farmed in the Grande Ronde Valley.
Agriculture is a major component of the economic structure in Union County.
A wide variety of crops including wheat, oats, barley, grass seed, alfalfa hay, seed potatoes, cherries, peppermint, peas, garbanzo beans, sugar beets, and evening primroses are crops grown in the rich valley soils of Union County. The Grande Ronde River, its tributaries, and deep wells supply irrigation water. Cattle, sheep, horses, emus, and llamas are raised in the valley and on the surrounding hills. Like agriculture, forestry has long played an important roll in the Union County economy. While logging activity and the production of wood products have been significantly reduced in recent years, they remain one of the largest employment sectors for the county.