The National Archives has the results of past electoral college votes, and its pages for each election show the state in which the candidates lived. The 1956 results list Dwight Eisenhower as a resident of New York. See here. Scroll down to see the state of each candidate.
It is extremely unlikely that Eisenhower really lived in New York in 1956. He was president of Columbia University before he became president in 1952, so of course he had a connection to New York in 1952. But in 1950 he and his wife Mamie had bought the only home they ever owned, a farm in Gettysburg, Pennsylvania. It needed renovation and wasn’t ready for their occupancy until 1954. Given that they did have that home from 1954 on, and also given that obviously he spent most of his time in the White House 1953-1961, it seems very unlikely he had a real residence in New York city in 1956.
This is perhaps relevant to the controversy over the residence of Robert F. Kennedy, Jr., which threatens his ballot status in New York.