The first explorer in Whitmore was probably John Work. The Hudson's Bay Fur Company sent work in a party of explorers from Fort Vancouver on the Columbia River to explore what are now Washington, Oregon, and California. John Work's group of twenty-eight men, twenty-two women, forty-four children and six Indians left Fort Vancouver on August 17, 1832 and returned on October 31, 1833.

They traveled in the upper Sacramento Valley, then east to Goose Lake and down to the Pit River. The party continued down the Pit River to Hat Creek, where they camped. From there they reached the headwaters of Cow Creek, and followed the divide between Old Cow Creek and South Cow Creek. Part of their path was probably what is now Tamarack Road. Work wrote [original spelling and punctuation]:

Fine Weather. The climate appears quite changed as we descend. Continued our course 15 miles S. by W. along the foot of the mountain, the road hilly and in places stony. We mistook our road or we would have been out in the plain [Millville Plain]. Some Indians quite naked came to the camp in the evening and received some trifles as presents. They were not the least alarmed or shy, but appear afraid of the dogs and horses. Some of the people visited their little huts. The women had all fled, but the men immediately offered their visitors food. The hunters were again out but without success, though there were a good many tracks of deer. . . . As we descend the wood is principally oak. . . . The hunters missed 3 grizle bears.

Work continued descending Cow Creek, which he called Canoe River. They set traps and caught two beavers, and killed fifteen deer and one elk. He said that the beavers were scarce and very lean. The party traveled west to the plains near Millville, then down to the Sacramento River. At the river they felled pine trees for canoes to continue their travels.