This process often took a long time locally, and as a region, the West has historically been more skewed to men than the East. My area of research, the Comstock Mining District in western Nevada, can provide an example. The first strikes were in January and June 1859. The first census was in late summer 1860. It documented a little more than 3000 adult people in the communities of Virginia City and Gold Hill. Of these, 111 were female 15 years or older. The largest single group of these were married speakers of Spanish.

By 1870, the population was showing a little more balanced, and this process was documented in each subsequent census through 1900. The peak population was in the mid 1870s, reaching probably a little more than 20,000 in the two towns.

The mines began to fail after 1880, so as the population shrank, families tended to linger longer than single men, offering even more correction to the gender imbalance. Despite all of this, the best balance was never more than one third adult female to two thirds adult male during the nineteenth century.

And then ... there was another strike, a "mini-bonanza" that occurred in 1903. This brought a new flood of single young men, and the gender balance that was being achieved by the turn of the century was reversed. The boom period lasted another decade and the community again began to shrink. At its smallest in the 1930s, there were fewer than 400 people still living in the two towns. Many of these were the old bachelor miners who were still hanging on hoping for the next boom, continuing to maintain a gender imbalance. The 1950 census showed a near gender balance of 56/44 percent, and after that the community began to show something approximating the national average (there are now fewer than 1,000 people living in the two towns).

The best way to achieve gender balance is with time - children arrive with the typical gender balance, and when old men die, the ratio begins to settle into the national average, but that process can take a long time.

edit: by way of a source - I deal with this in my book, The Roar and the Silence: A History of Virginia City and the Comstock Lode (1998)