Get a good view of the breathtaking beauty of the San Bernardino Mountains when you visit Crestline. It is located in San Bernardino County, California, USA. The town has a small population – 10,770 as of the 2010 census. Adjacent to its location is the Lake Gregory, a man-made lake, where you can enjoy a refreshing swimming. There’s an amazing water slide located at the eastern part of the lake.