noun
location without an address; unnumbered plot of land
Refers to a piece of land or a location that does not have a registered address or lot number, often in rural or undeveloped areas.
その小屋は番外地にあるので、郵便物は届かない。
That hut is on an unaddressed plot of land, so mail doesn't reach it.
地図で番外地と書かれている場所は、住所が割り当てられていない。
Places marked as 番外地 on the map have no assigned address.
無番地 also means an unnumbered plot, but 番外地 is more common in legal and real estate contexts.
Compound of 番外 (bangai, 'outside the numbering') + 地 (chi, 'land'). The term is used in Japanese land registration to denote parcels without an assigned lot number.