Grand Opera House
Crown Street, New Haven, CT
Destroyed (fire): April 25, 1915
Source: NYT, April 26, 1915
The formal name was the Grand Opera House, not Peck's Opera House as noted in previous itineraries, to which it was sometimes referred as it was owned and managed by Clark Peck.
When Peck died in 1890 he left what the NYT called 'a peculiar will' (below).
Harry Miner's American dramatic directory for the season of 1884-'85
by Harry Miner, 1884, p. 86.
As to the audience
In this article the Modernism Lab at Yale University sought to correct the audience size given in the NYT (opposite) asserting that the audience size was probably closer to 1,000. They based this on the maximum seating capacity of the 'New Haven Opera House', their source being:Yale and "The city of elms," by William Emery Decro, 1885, p. 114). However, the New Haven Opera House was a different venue that Decro describes as "a very cosec little theatre".
The NYT is likely correct as Wilde lectured at (Peck's) Grand Opera House where the seating capacity was 1,600.