Jefferson County was created in 1914, out of territory that was once part of Crook County. The county is named after Mount Jefferson, the second highest peak in Oregon (elevation of 10,497 feet).
The county encompasses 1,791 square miles (1,146,639 acres). About half is privately owned, while a quarter each consists of part of the Confederated Tribes of the Warm Springs Reservation and federal lands.
Geographically, the county includes portions of the Cascade Mountains to the west and the Ochoco Mountains to the east. Elevation ranges from 1562 ft. at Warm Springs to the top of Mt. Jefferson. The County owes much of its agricultural prosperity to the arrival of the railroad in 1911 and irrigation water in 1946, which created a land rush and a population boom in Madras and the surrounding area; the farmland around the town would eventually produce some of the world’s finest mint and seed crops.
Rainfall averages 9-10 inches annually in Madras, 12-15 inches in much of the eastern part of the county with averages of 20-80 on the timbered east slopes of the Cascades. The growing seasons average 90-120 days at the lower elevations.
A combination of volcanic and sedimentary material makes up Jefferson County geology.
Deep, faulted stony canyons, buttes and varicolored sediments are characteristic of this area. The ash soils in this area potentially can produce large amounts of sediment from accelerated runoff when exposed, compacted, or channeled.
Detailed Soil Surveys have been completed on all parts of the District that are not federally owned (http://websoilsurvey.nrcs.usda.gov).
Many springs appear in canyon walls where the more porous Deschutes Formation hits the impermeable John Day Formation; groundwater flows along the interface between the formations until it reaches the ground surface or is tapped with a well. Higher nitrates have been found in many of these springs, but the source is unconfirmed.
Agriculture drives Jefferson County’s economy. Gross income from agricultural commodity sales totaled $74.4 million and contributed more than $260 million to the Central Oregon economy in 2012. By comparison, agricultural commodity sales in Deschutes County averaged $26.1 million and contributed $91.3 million in total economic impacts.
The upper Trout and Willow Creek watersheds near the Jefferson/Crook County line consist of coniferous forest. These forests are harvested for timber and grazed by cattle. Middle elevations consist primarily of juniper savanna interspersed with treeless grassland. Both types of lands are grazed by cattle as part of large ranches. Juniper density has increased dramatically over the past 90 years. The increase in juniper has reduced the uplands’ ability to collect and store precipitation.
Irrigated croplands cover the lower elevation areas known locally as Mud Springs, Gateway, Little Agency Plains, Agency Plains, Culver, Henderson Flat, and Trail Crossing. Irrigated crops include grass seed, alfalfa, seed potatoes, carrot seed, grains, flower seed, hay, nursery crops, herbs, mint, onion seed, garlic, hemp and some vegetables.
Approximately 58,990 acres of the 64,142 irrigated cropland acres are within the North Unit Irrigation District (NUID). Wickiup Reservoir is the primary water source. Water is routed in the Deschutes River from Wickiup Reservoir to Bend and then diverted into 65 miles of main canal to Jefferson County.
Since the formation of NUID, more than half the land has been converted from surface to sprinkler irrigation. Conversion is a necessity due to rising labor costs and reduced water supplies.
The remainder of the irrigated land lies along smaller streams, and irrigation is limited to those stream flows.
The small amount of non-irrigated cropland is devoted to a wheat/fallow rotation and is at best, marginal wheat land. Non-irrigated crops include hay, winter wheat/summer fallow, pasture, and perennial vegetation planted under the Conservation Reserve Program (CRP).