The Christmas tree tradition started in Germany in the 16th Century. A Protestant reformer was inspired by the stars shinning through the evergreen trees at night. He wanted to recreate the scene so he put an evergreen tree in his house and wired the branches with candle light.
Christmas was brought to America in the 1800s. It was not always a popular holiday. In fact, people were fined for hanging up Christmas decorations in Massachusetts. It wasn't until 1846 when Queen Victoria and her German Prince Albert, were sketched in the newspaper standing around a Christmas tree. Once that picture went public, Christmas became favored on the east coast of America.
Read more here