The municipality covers 2,100 square kilometres, and most of it is Serra da Canastra National Park — 71,525 hectares of high cerrado grassland with a perimeter of 173 kilometres. That leaves about 7,000 people, by the 2020 count, living around the edges of a protected wilderness rather than the other way round. The town centre sits at 818 metres on a plateau roughly ten kilometres east of the park entrance. Belo Horizonte is 334 kilometres away; the nearest regional centre of any size, Piumhi, is 58, and as recently as 2000 the connecting roads were still unpaved. São Roque de Minas has been a municipality since 1938. As of 2007 it had no bank at all.

Queijo da Canastra is made from raw cow's milk, pressed by hand and left to mature — traditionally twenty-one days, though plenty of producers now push it to forty or beyond. The flavour is strong and slightly peppery, and cheesemakers here will tell you it comes from the specific combination of altitude, native pasture, mineral soils and cold clear water that the Canastra provides and nowhere else quite duplicates. It is not a sideline. Agriculture supplied 31 of the 56 million reais of municipal GDP in 2005, with 778 rural producers working 139,000 hectares and 55,000 head of cattle on the hills; roughly 2,200 people depend on farming directly. The region's cheese farms are now strung together as the Rota do Queijo Canastra, a signed route that brings visitors up the same unpaved roads the milk trucks use.

Serra da Canastra holds the largest known population of maned wolves — long-legged, russet, more stilt than wolf, and most often seen at dusk crossing the open campo. Giant anteaters work the termite mounds on the plateau in broad daylight, which is the reason a good share of the wildlife photographers who come to Brazil come here. The rarest resident is a duck. The Brazilian merganser, pato-mergulhão, needs fast, exceptionally clear rivers to hunt in, and fewer than 250 are thought to survive anywhere; the streams draining the Canastra are among its last strongholds. Protecting them means protecting exactly the water quality that the cheesemakers downstream also depend on, which is a tidier alignment of interests than conservation usually gets.

Numbers describe São Roque de Minas better than adjectives do. Its human development index in 2000 was 0.766, ranking it 186th of 853 municipalities in Minas Gerais — comfortably in the upper third, well short of wealthy. Literacy stood at 88 percent, life expectancy at 74. Fourteen schools, from pre-primary through middle, handled 1,250 students. Health care came down to four clinics and one hospital with fourteen beds; anything serious meant a drive to Passos, Piumhi or Franca, over roads that were still gravel for much of the way. This is the ordinary texture of life at the head of the São Francisco: a small town, a long way from a hospital, holding the source of a river that a few million people downstream cannot do without.