When the first sawmills were established, they were usually small water powered facilities located near the source of timber, which might be converted to grist mills after farming became established when the forests had been cleared. Later, bigger circular sawmills were developed in the lower reaches of a river, with the logs floated down to them by log drivers. In the broader, slower stretches of a river, the logs might be bound together into timber rafts. In the smaller, wilder stretches of a river, rafts couldn't get through, so masses of individual logs were driven down the river like huge herds of cattle.
The log drive was one step in a larger process of lumber-making in remote places. In a location with snowy winters, the yearly process typically began in the fall when a small team of men hauled tools upstream into the timbered area, chopped out a clearing, and constructed crude buildings for a logging camp. In the winter when things froze down, a larger crew moved into the camp and proceeded to cut trees, cutting the trunks into 16-foot (5 m) lengths, and hauling the logs with oxen or horses over iced trails to the riverbank. There the logs were decked onto "rollways." In the spring when snow thawed and water levels rose, the logs were rolled into the river, and the drive commenced.
To ensure that logs drifted freely along the river, men called "log drivers" or "river pigs" were needed to guide the logs. The drivers typically divided into two groups. The more experienced and nimble men comprised the "jam" crew or "beat" crew. They watched the spots where logs were likely to jam, and when a jam started, tried to get to it quickly and dislodge the key logs before many logs stacked up. If they didn't, the river would keep piling on more logs, forming a partial dam which could raise the water level. Millions of board feet of lumber could back up for miles upriver, requiring weeks to break up, with some lumber possibly lost if it was shoved far enough into the shallows. So when the jam crew saw a jam start, they rushed to it and tried to break it up, using peaveys and possibly dynamite. This job required some understanding of physics, strong muscles, and extreme agility. The jam crew was an exceedingly dangerous occupation, with the drivers standing on the moving logs and running from one to another. Many drivers lost their lives by falling and being crushed by the logs.
Each crew was accompanied by an experienced boss often selected for his fighting skills to control the strong and reckless men of his team. The overall drive was controlled by the "walking boss" who moved from place to place to coordinate the various teams to keep logs moving past problem spots. Stalling a drive near a saloon often created a cascade of drunken personnel problems.
A larger group of less experienced men brought up the rear, pushing along the straggler logs that were stuck on the banks and in trees. They spent more time wading in icy water than balancing on moving logs. They were called the "rear crew." Other men worked with them from the bank, pushing logs away with pike poles. Others worked with horses and oxen to pull in the logs that had strayed furthest out into the flats.