In Pennsylvania the timber rattlesnake is a candidate species, meaning that its future status could be upgraded to threatened or endangered. The Pennsylvania Fish and Boat Commission is currently working on a statewide inventory and assessment grant pertaining to this species. In Pennsylvania, this species is primarily threatened by over-exploitation by snake hunters, habitat loss and fragmentation.

This species ranges from central New England southward to northern Florida and west to eastern Texas. In the northeastern United States, it inhabits primarily upland forests where rocky outcroppings and talus slopes occur. Throughout much of Pennsylvania, this is the only species of rattlesnake which occurs. In the northeast there are two main color variations – a yellow phase and a black phase. Individuals of either phase also exhibit varying degrees of crossbanding. Mature individuals average between 36 and 60 inches. Timber rattlesnakes prey primarily on rodents, but ground-nesting birds are also consumed. Like all rattlesnakes, this species is viviparous with an average litter size of 5 to 9 young.