The Center for Indian Country Development reports…

The lowest category, in light yellow, shows reservations where fewer than 55 percent of households have broadband access. This access rate is well below the national average of 78 percent as well as below the average rate in completely rural counties of 65 percent,5 and is evident in several geographically large reservations in the Southwest, Northern Plains, and Intermountain West. However, other large reservations in the same areas have rates closer to national and rural county norms. It is also evident from Figure 1 that a few reservations match or exceed the national average.
Broadband access levels for many geographically small reservations are hard to discern in Figure 1 but can be analyzed statistically. Across 262 federally recognized reservations, in the typical (median) reservation, 61 percent of households have broadband access. This percentage is significantly lower than the percentage of households with broadband access in the typical U.S county which is 69 percent. In the typical county that overlaps at least one reservation, 70 percent of households have broadband access.
The Census Bureau has shown that counties’ rates of broadband access are positively correlated with income.6 We have found the correlation between income and broadband access for reservations is very similar as to counties.
They recognize that not only is lack of broadband more prevalent in lower income households, it may be a contributing factor…
However, the relatively low rates of broadband access in reservation communities may also add to their economic development challenges. Enhanced Internet access may not boost all types of reservation economic activity. For example, if reservation residents increasingly purchase consumer goods online from remote suppliers, employment at local retail outlets may fall. However, the net effects of enhanced access are generally considered positive for economic vitality, including through channels such as increased productivity at local businesses, increased sales to consumers outside the reservation, improved life-style and government services that attract residents, improved medical and educational services, and more.7 For these types of reasons, tribes and tribal organizations are taking steps to enhance Indian Country’s broadband access