Nineteenth-century frontier women's lives were analyzed in the context of a remote Pacific frontier in the years 1850, 1860, and 1870, in order to add a quantitative element to the recent scholarship on pioneering women. Given Clark County, Washington's proximity to Oregon's Willamette Valley, it was supposed that the economy, sex ratio, and fertility would conform to that of agricultural frontiers. Instead, the sex ratio was typical of Far West extractive economies; the economic base evolved from fur trade to farming; and fertility climbed dramatically, beyond that of contemporary agricultural areas. High sex ratios were assumed to cause near universal marriage of adult women. A large percentage of women were married, but it remained static throughout the period.
The population of Clark County differed somewhat from that of Oregon, and male from female, with regard to origins. Expectations were that women would be similar to men in this regard, and that Clark County would be similar to Oregon. However, while the differences decreased between women and men as the settlement matured, females had a tendency to be more native to the territory and less foreign to the United States than males. The general Clark population was more foreign to the United States than that of Oregon. Mapping age cohorts revealed an inverse relationship between age and westward movement, and pointed up the emergence of portals to the Far West and circulation of population among the Pacific territories. These findings reflect the origin of Clark County as a British settlement and support migration theory.