John Manning remained in Highland, Wisconsin until 1860, and then headed West to Colorado at the time of the gold rush around Pikes Peak. When gold was discovered in Montana, Manning headed North into Montana Territory & later into what is now Idaho, and eventually settling for a time in Beartown, Montana. Beartown, located at that time in Deer Lodge County, Montana, was, for a time in the late 1860s & early 1870s, the sight of a major gold rush, attracting upwards of 5,000 prospectors, who often were referred to as the Beartown toughs. During his time in Deer Lodge County, he served as Deputy Sheriff for the county, covering an area stretching from the Idaho border to the Canadian border. While living in Deer Lodge County, Manning was known for his interest in horse racing, and could often be seen with one of his racehorses at Olin's Racetrack in Deer Lodge Montana.