Afghani Ethnicity

Light green, brown and white areas are Uzbeks and Tajiks (generally anti-Taliban)
Yellowish area Shia Hazara (supported by Iran and generally anti-Taliban)
Gray area encompassing Herat/Kandahar/Kabul are Pashtuns (not exclusiviely sympathetic to Taliban but their ethnic base nevertheless)

TW: There are currently about 28MM Afghans. Their population growth rate is one of the world's highest by 2050 the population may approach 70MM.

Afgahnistan is an ethnic potpourri. The Taliban are, however, predominantly Pashtuns (understanding there are numerous tribes amongst the Pashtuns). The Taliban achieved power pre-9/11 through the use of the Pashtun brethren from Pakistan. There was a brutal civil war within Afghanistan pitting the northern Uzbeks/Tajiks/Hazara against the Pashtuns albeit with a significant amount of double-crossing based upon payoffs and bribery.

The notion that geography can be hived off based on ethnicity is attractive although dubious:

From Tom Ricks at Foreign Policy:
"In the closing talk of the COIN conference, Gen. David Petraeus [US Centcom commander] said that 70 percent of the violence in Afghanistan is in just 10 percent of the country's districts. (Meaning that a troop-intensive counterinsurgency campaign might not need as many troops as you might think.)

I guess he missed the opening talk by former State Department counselor Eliot Cohen, author of the terrific study Supreme Command, about civilian leadership in war. One metric that drives him batty, he said, is when officials say, "Well, 75% of the violence occurs in 10 percent of the country," an approach Cohen said he finds, "profoundly misleading." First, he said, if we aren't there, we don't know how much violence is occurring. Second, he said, the place might be "completely quiet" because the Taliban have already won in that area..."
http://news.bbc.co.uk/hi/english/static/in_depth/world/2001/war_on_terror/key_maps/ethnic_hazara.stm