Malta
none

Marshall Islands
claims US territory of Wake Island

Martinique
none

Mauritania
Mauritanian claims to Western Sahara have been dormant in
recent years

Mauritius
Mauritius claims the Chagos Archipelago (UK-administered
British Indian Ocean Territory), and its former inhabitants, who
reside chiefly in Mauritius, were granted UK citizenship but no
right to patriation in the UK; claims French-administered Tromelin
Island

Mayotte
claimed by Comoros

Mexico
prolonged drought, population growth, and outmoded practices
and infrastructure in the border region have strained water-sharing
arrangements with the US; the US has stepped up efforts to stem
nationals from Mexico, Central America, and other parts of the world
from illegally crossing the border with Mexico

Micronesia, Federated States of
none

Midway Islands
none

Moldova
Moldova and Ukraine have established joint customs posts to
monitor transit through Moldova's break-away Transnistria region
which remains under OSCE supervision