The Gold Rush took place in California and it made everybody want to pack up and move west toward California in hopes of gold and riches. Manifest Destiny was the belief in which America/Americans needed to expand. People hearing about gold in the west only added on to the speed of people getting up and leaving to expand their grounds to the west and hopefully become rich. Basically, once it was learned that there was gold in the west/the gold rush period, more people began to move from where they lived and instead moved around California, which was indeed, expansion.