Your friendships don't have to end simply because you relocated! This is especially true in this day of cell phones, email, social media, Google Hangouts, and Skype.
Lots of adults make new friends at the companies they work for. Some join groups in their area that share their same interest, others gradually make friends with those at the gym, neighbors, or over time as they keep bumping into the same people at grocery stores, local restaurants, church, or wherever people congregate.
One great resource is Meetup.com which lists several hobby groups and various other enthusiasts interested in similar activities who get together monthly or bi-weekly. Taking a workshop or continuing education "How to" class, sports bars, nightclubs, and hotel lounges on weekends can be a social hot spot. Being open to visiting a nearby city that may have more people and more activities going on is another option.
Generally speaking it takes time to become accumulated to a new area and discovering where people in your age group or share your interest congregate. Local and community newspapers often feature a list of upcoming activities and events.
Lastly you can always approach people of your age group and ask them where do people go to have fun or meet others. Most likely someone will give you some viable suggestions.