By 1860 the population of Texas had spread as far west as

Here you go:

Explanation:

The city of El paso.

By 1860 the population of Texas had spread as far west as Texas already had 600000 population.

Explanation:

In 1860 the population of Texas increased rapidly in geometric ratio for the growth of cotton, tobacco and silk. This materials stimulate the growth of population from 600000 to 800000000. The favorable climate and soil type is the responsible factors for enhancing field under cotton production.

Its increased the foreign trade and earned money which was available to the people and for their better living style. The land in the river valley of California extended and expanded. The effects of physical barriers which might be the restraints fully removed under the dominance of demand and equally supply.