The Copper River Valley roughly covers much of the linguistic and cultural area that the Ahtna people lived in for centuries.
The exact population of the region is not hammered down, and never has been.
This is partly due to the fact that today it is an unincorporated region of Alaska. There is no mayor, no city government, no local taxes... Native villages do have local government, in the form of village councils and community organizations. But the overall community is highly dependent on volunteerism to operate basic services, such as fire departments, senior centers and so on.
Around 3,000 people live in the Copper River Valley, in dozens of self-defined communities. When you travel through the region, you may not be aware that the little dirt roads lead back to homes and homesteads that aren't visible from the road. Glennallen looks like the largest "town" but it is not very large when compared to the total population of all the combined other parts of the region.
The Copper Valley is defined, by locals, as starting at Eureka Summit on the Glenn Highway; around Tiekel on the Richardson Highway north of Valdez; around Mentasta on the Tok Cutoff; around Paxson on the north Richardson Highway, and around Maclaren River Lodge on the Denali Highway. To the southeast, it includes Chitina, McCarthy and Kennicott.