Location Routing Number (LRN)

The Location Routing Number (LRN) is a ten-digit number designed to look like a telephone number. An LRN is assigned to each ported telephone number and is used to route calls through the PSTN to the switch serving the ported number. The LRN is intended only as the network address of the serving switch and is not intended to convey any rate area information such as would be used to determine whether a call is local or long distance.

The same ten-digit LRN can be used for every ported number served from the switch to which the LRN's NPA-NXX is assigned. The LRN is not a telephone number. The same ten-digit string could be used both for an LRN and for an individual telephone number assigned to the LRN's switch. However, the best practice is to avoid using the same ten-digit string for both a consumer's telephone number and an LRN. Local Number Portability (LNP) relies on the location routing number.

There are currently over 500 million LRNs.