The African country with Lake Malawi along its eastern border is Malawi.
Lake Malawi occupies much of Malawi's eastern boundary and is one of the African Great Lakes. It is also called Lake Nyasa, especially in Tanzania and Mozambique. The lake is famous for its clear water and exceptional diversity of freshwater fish, particularly cichlids, many of which are found nowhere else.
Malawi is a landlocked country in southeastern Africa, bordered by Tanzania, Zambia and Mozambique. The lake extends into all three countries, so identifying it solely with Malawi can be misleading. Under different national naming conventions, its northern and central waters are called Lake Nyasa, while “Lake Malawi” is the official name used by Malawi.