How many letters does the top answer for “city in khartoum” have?

The most common answer is khartoumnorth (13 letters).

Crossword clue: city in khartoum

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

khartoumnorth 13 letters wd-fact-v3

omdurman 8 letters wd-fact-v3

a battle (1898) in which an English and Egyptian army under Kitchener defeated the Sudanese