What is the area for area code 421?

Answer 1

There is no area code +1 421 in North America (USA, Canada, etc.)

+421 is the telephone country code for Slovakia, used for international calls.

(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 North America (USA, Canada, etc.) uses 011, Japan uses 010, Australia uses 0011, and many other countries use different prefixes.)

Answer 2

There is no area code for (421) within the United States. What you are looking at is an international calling code for Slovakia. Slovakia is located along the border of the Czech Republic near Russia.