Where It All Goes Down
Tabasco, a Southern Mexican State, during the 1930s
The Power and the Glory is loosely set in the southern Mexican state of Tabasco during an anti-Catholic purge. Greene had visited Mexico during this time of religious persecution and had seen its effects up close and personal.
The events in the novel transpire years into the suppression of the Catholic Church: houses of worship have long been destroyed or converted into government buildings, children have no memories of going to Mass, and most of the priests in the state have been hunted down and executed. The protagonist of the novel is apparently the only living priest in the area—no pressure or anything.
Locations
The action takes place mostly in small villages and plantations the priest visits or in the unnamed Capital. The narration follows the priest around, but also adopts the point of view of people near and far away from him.
While Greene keeps the exact locations somewhat vague (he doesn't actually name the state), he brings them to life with vivid description. We're treated to the sights, sounds, and smells of a river port, a city square, a tiny dental office, police barracks, jail cells, city residences, impoverished huts, plantation barns, and a seedy hotel where you can buy illegal booze.
Geography
Forests, rivers, and mountains dominate the terrain and make both travel and escape difficult. Gee, thanks Mother Nature. The mountains on the border are passable, at least when it's not raining, but come rain season you'd have better luck scaling the Wall in Westeros with a couple of toothpicks than getting over that terrain. The priest knows that once the rains begin, he has no chance of escape. Dry time is the only escape time.
Environment
In this world, it's always blazingly hot…until the rains come. Then it's wet and muddy, and being on the run is even less fun than when it's sunny. A climate of extremes, right? Just like the political climate in the state. Once the Church was prosperous and powerful, and now it is intensely and violently suppressed, kind of like the two main characters of the novel. The lieutenant is hot on the trail of the priest, and the priest muddles through his mission like a man lost in a downpour.