Where in North America is area code 151?

There is no area code 150 in North America (USA, Canada, etc.); North American area codes cannot have '1' as the first digit.

North America uses telephone country code +1, and there are 9 area codes beginning with +1 50, scattered around the US and Canada. You need the next digit to narrow down the location any further.

(The plus sign means "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but Japan uses 010, Australia uses 0011, and many other countries use different prefixes.)