It lies along the Glenn Highway at its junction with the Richardson Highway, 189 road miles (304 km) east of Anchorage. It is just outside the western boundary of Wrangell-St. Elias National Park and Preserve.
According to the United States Census Bureau, the CDP has a total area of 114.9 square miles (297.5 km²), of which, 114.1 square miles (295.5 km²) of it is land and 0.8 square miles (2.0 km²) of it (0.66%) is water.
In 1899, the U.S. Army built a pack trail for summer use between the port of Valdez and Eagle, which passed through the Copper River Valley. In the early 1900s, the trail was widened and became the Richardson Highway.
During World War II, the United States built a series of military bases in Alaska, primarily for the purpose of supplying aircraft and other war material to Russia by way of Alaska and the Russian Far East as part of the Lend-lease program. This made it difficult for the Germans to the east and the Japanese to the south of Russia to interfere with the supply operation. As part of this operation, highways were built to supply the bases. The major highway project of this effort was the Alaska Highway from Dawson Creek, British Columbia, Canada to the existing Richardson Highway at Delta Junction, Alaska and thus to Fairbanks via the Richardson Highway. Another project was the Glenn Highway, which connected Anchorage, Alaska's largest city, with the Richardson Highway, and thus with the rest of Alaska, Canada, and the then-48 United States.
Construction for the Glenn Highway began at a camp on the Richardson Highway in the Copper River Valley named Glennallen after two U.S. Army explorers of the late 1800s: Capt. Edwin Glenn and Lt. Henry T. Allen. The highway was completed in 1945. Glennallen developed as a small community around the site of the camp. It became a commercial center for motor traffic along the Glenn and Richardson highways. It is one of the few communities in the region that was not built on the site of a Native village.
During the 1950s and 1960s, another highway, the Tok Cut-Off, was constructed from a point 15 miles north of Glennallen to the community of Tok, 135 miles east on the Alaska Highway. This enhanced Glennallen as a commercial center. Also, in 1956, a Jesuit school was opened, called Copper Valley School. This facility increased the population considerably by bringing to the region a number of staff and students from Holy Cross Mission in Western Alaska. In 1961 "Glenallen" was officially renamed "Glennallen" by the US Postal Service, adding the extra 'n'.
Glennallen's economy grew with the construction of the Trans-Alaska Pipeline System from 1975-1977 and the continuing service needs of the pipeline. The economy of the area was negatively impacted by the construction of the George Parks Highway, which connected Anchorage to Denali National Park and Fairbanks along the Alaska Railroad route, bypassing Glennallen.
There were 204 households out of which 36.8% had children under the age of 18 living with them, 56.4% were married couples living together, 6.4% had a female householder with no husband present, and 33.3% were non-families. 27.0% of all households were made up of individuals and 5.4% had someone living alone who was 65 years of age or older. The average household size was 2.63 and the average family size was 3.31.
In the CDP the population was spread out with 31.8% under the age of 18, 9.6% from 18 to 24, 27.4% from 25 to 44, 26.2% from 45 to 64, and 5.1% who were 65 years of age or older. The median age was 32 years. For every 100 females there were 106.7 males. For every 100 females age 18 and over, there were 110.0 males.
The median income for a household in the CDP was $38,846, and the median income for a family was $40,909. Males had a median income of $29,375 versus $28,125 for females. The per capita income for the CDP was $17,084. About 4.6% of families and 8.04% of the population were below the poverty line, including 12.8% of those under age 18 and 3.1% of those age 65 or over.
Prince William Sound Community College, on mile 188 of the Glenn Highway, and Alaska Bible College are located near or in Glennallen.
ALASKA DEPARTMENT OF ENVIRONMENTAL CONSERVATION ISSUES PUBLIC NOTICE OF ISSUANCE OF AIR QUALITY PERMIT, AIR FORCE RESEARCH LAB, MILEPOST 11.3 TOK CUTOFF
Jul 04, 2009; JUNEAU, Alaska, June 29 --The Alaska Department of Environmental Conservation issued the following public notice: Body of Notice:...