While I haven't checked all my files yet, I do have the State Sportsmen's Convention held in New York in 1866. Found it in the New York Times.
In the State shoot, Robert Newell’s side won by 21 birds, and the ties of yesterday were shot off.
Today, J. Wilmer, of Niagara Falls, won the first prize, and Robert Newell, of Buffalo, the second.
[ THE NEW YORK TIMES, June 1, 1866, page ]
I've got early State Championships for Illinois in 1874; Nebraska in 1876; Texas in 1876; Missouri at 1877; Iowa in 1877; New Jersey in 1897; Connecticut in 1880; Ohio in 1883; Georgia in 1885; Wisconsin in 1885; Minnesota in 1887; Kansas in 1889; Arkansas in 1890; Pennsylvania in 1890; Arizona in 1892; Washington in 1895; North Dakota in 1895; Mississippi-Louisiana State Shoot in 1897; West Virginia in 1897; Maryland in 1899; Tennessee in 1899; Virginia in 1899; North Carolina in 1901; Utah in 1901; Oklahoma in 1901; Rhode Island in 1903; Idaho-Utah State Shoot in 1905; Vermont in 1908; South Carolina in 1910; Wyoming in 1911 and Delaware in 1914.
I'd be interested in information on any earlier State Championships and/or corrections & additions.
There were some states that held state championships before they had a State Association or the reorganization of a new State Association. Many early State Associations were Sportsmen's & Game Protection organizations which later changed their names. New Jersey's first state championship (State Shoot) was in 1879 and we had about four or five more randomly up to 1897, the date used as our first tournament under the NJ State Sportsmen's Association.
I actually have earlier State tournaments for Massachusets prior to their 1911 or 1912 beginning. Of course the 1885 date I believe was a glass ball tournament.
The Massachusetts trap-shooters had a tournament at Walnut Hill, December 31. The Massachusetts Rifle Association team won the champion badge, making the best average of three winning scores. The individual badge was won by Mr. Dickey. The second medal was won by Mr. Black.
[ OUTING, Volume V, Issue 6, 1885, page 474 ]
The team and individual badges of the New England Trap Association, held by the Worcester Club, was shot for January 2, at the coal Mine Brook Range, Worcester. The contestants for individual badge were Dickey, Eager, Perry, Stark, Tidsbury, and Kirkwood, and it was won by Mr. Dickey with the score of 44. The team badge was won by the Worcester team, making a score of 74 against Massachusetts Rifle Association, 69. In the individual match there was a possible 50, and in the team match a possible 20; balls thrown on 18 yards rise.
[ OUTING, Volume V, Issue 6, 1885, page 474-475 ]
At the third annual trap shooting tournament of the Massachusetts State Trap Shooting Association, held on the Worcester Sportsmen’s club’s grounds, June 6, S. W. Putnam, of Fitchburg, shooting the Black Shells, won first honors by breaking 141 out of 150. F. O. Williams, of Boston, shooting The Black Shells, won second place with a score of 140 out of 150.
[ SPORTING LIFE, June 14, 1913, page 39 ]
California is one of those states that held joint State Championships. The California-Nevada State championship was held to at least 1914 due to the small amount of trap shooters in that period.
Here's an earlier State Shoot for you.
TRAP IN CALIFORNIA
Annual Tournament of the California State Sportsmen’s Association
The annual tournament of the California State Sportsmen's Association opened May 3 at the Oakland race track and continues for three days. The weather was all that could be desired and the attendance larger than usual on such occasions. Great care was taken in selecting the birds, and, as
the day wore away, it was evident that good judgment had dictated the choice, for a livelier lot of pigeons were never trapped than those which sharpened the zest of the sportsmen.
THE SECOND DAY, MAY 4.
The Fay diamond medal contest was the event of the second day of the California State Sportsmen's Association tournament at Oakland track. This prize was captured by M. Chick, of San Diego, who tied Robinson, the holder of the medal last season, on 19 birds in a 20-bird match. In shooting off the tie with five birds Robinson missed his second pigeon, swift "incomer," giving Chick the medal on five straight hits.
Chick has already held the Fay medal for three seasons, and lost it to Robinson last year.
A 10-bird match was arranged, with an entrance fee of $5, for which there were 18 entries. Robinson, Slade, Chick, Fendner and McMurchy tied on 10 birds each and divided first money. The medal match was then made up with an entrance fee of $5 and shot off.
In the five-bird tie for the medal between Chick and Robinson the scores stood as follows:
In a third match of 12 birds, $5 entrance, first money was divided between Richards, Warder, Fendner and Morrison on clean scores. 1 The last match of the day was one of 10 birds, with entrance money fixed at $5. Chick and Rice divided first money on clean scores.
[ SPORTING LIFE, May 25, 1895, page 25 ]
I agree with KennyRay that the first Nebraska State meet was in 1876.
The article below (i hope) is from the May 28, 1918 Omaha World Herald. It stated that the meet would be the 42nd annual meet. The 1918 meet was held in Fremont over four days in late May. They had 5 traps. In addition to the "usual awards" they had 4 silver cups for the best averages on the 16 yard targets.
The meet had 150 targets the first day and 200 on each of the following 3 days. The "Jack Rose" system will prevail. The first 100 targets on the second day will be for the state championship trophy. Charles Gelletly of Sutton was the defending champion. Interstate handicap from 16 to 23 yards was shot on the morning of the fourth day and the amateur championship of the state on the afternoon of the fourth day.
On the 30th the World Herald reported that John Nelson of Boelus won the tournament with a 98. P. R. Miller of St. Louis led the professionals with a 99. R.J. Middaugh of Fremont won the Interstate Trapshooters Nebraska Handicap with a 97. T.H. Lewis of Omaha had the highest of the amateurs. In the handicap event there were 7 professionals, 8 16 yard shooters, 19 shooters at 18 yards, 7 shooters at 19 yards and 10 shooters at 20 yards. It looks like only the pros were all the way back to the 23.