Population growth in the United States presented serious challenges at the eve and during the 19th century. The US experienced an upsurge of population increase, which was a surprise to the ruling government. The incidence was characterized by urbanization and movement of natives from rural to urban centers. Many cities cropped up and the economy grew steadily. Further, the planning department had to censure the government to increase resources to cater for the swelling number of people (Greene and Virginia 90). The Congress passed several laws to govern the internal and external movement of people. The skyrocketing upsurge of the population was orchestrated by increase in fertility rates, decreased life expectancy, reduced mortality rates, internal and external immigration, and the condensed age structure of the population. All these factors were eminent in the US during the 19th century.Population growth is significantly influenced by population growth. The rate at which people move in and out of a nation greatly affects the rate of sample upsurge. Throughout the history, population upsurge in the US has been influenced by both legal and illegal immigrants. Before the formation of regulations governing immigration, many people from the war-tone countries sought refuge in the US (Hartman 99). The US was seen as peaceful and could accommodate many people irrespective of their origin. The population expansion index was elevated by the indeterminable movement of people with diverse demographic features. The US experienced substantial population expansion index net out migration due to the energy boom (Greene and Virginia 90). Further, the move by the immigration department to extend amnesty and mercy to the refugees escalated the rate at which people crossed internal borders. Natural and artificial calamities that affected world nations contributed to the movement of people (Greene and Virginia 90). Due to the collated financial and social resources, the affected people saw the US as harmonized and appropriate destination where peace was eminent.The influx in the number of immigrants led to the increase in birth rates. Research demonstrates that the increase in birth rates as compared to death rates elevates the rate of population growth. Today, an average woman in the American society bears a limited number of children, which is usually two. During the 19th century, illiteracy was eminent. Birth control plans had not taken roots (John 78). Women could bear children irrespective of the resources for maintaining the population. The number of women who could access reliable mechanism of controlling fertility were few. The phenomenon also contributed to the increase on the number of women who could be married (Walton 67). Before the entrance of the immigrants, especially the Europeans, birth rates were low. The underlying principle was that the Native Americans could breastfeed their infants for four or three years (John 78). Prolonged breastfeeding accomplishes contraceptive effect in human bodies. The amount of time dedicated to breastfeeding derailed population growth before 19th century. The entrance on the Non-Natives enlightened the Natives about early weaning of the infants. The weaning effect condensed the fertility period, hence increase in births.The concerted efforts dedicated to sanitization and improvement of health facilities were of paramount importance in elevate the population. Some fatal diseases like cholera, polio, and tuberculosis were discovered. Subsequently, their cure and preventive vaccines were invested. The phenomenon reduced death rates while escalating the rate of human growth. Healthcare also spread to the communities who joined the armed forces during moments of war. The soldiers also engaged women, who bore children, hence escalating the sample growth. Modern antibiotics were also discovered to cure the subsequent diseases of bacteria. The ailments used to cause deaths and reduction in fertility. The amount of time and resources, which were previously dedicated to children and conjugal engagements, were directed towards alleviation of diseases.