According to ELIAS

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The home team won all 15 games on the MLB slate on Tuesday night. That’s the most games in one day, all won by the home team, in major league history. The previous record was 12 games on May 23, 1914. There were three major leagues in 1914, the National (four games that day), American (four) and Federal (four), which had a two-year lifespan (1914 and 1915). Source: ELIAS