Territorial expansion refers to the process by which a country increases its land area, often through acquisition of new territories. This can occur through various means, including military conquest, treaties, or colonization. Countries may seek expansion to gain resources, enhance security, or increase their influence. Historically, many nations have pursued territorial expansion, such as the United States during the 19th century with its Manifest Destiny ideology. This led to the acquisition of vast lands, including territories from Mexico and the purchase of Alaska from Russia. Such actions have shaped national borders and influenced global politics.