Where in North America is area code 950?

There is no area code +1 950 in North America (USA, Canada, etc.).

The 950 prefix is special in North America. It is used to connect to long-distance carriers by dialing a 7-digit number (950-xxxx), which then gives a secondary dial tone for the calling card number and destination telephone number. This arrangement is called "Feature Group B" long-distance access.