Dartmouth has summer programs for high school students, and they may be engaged in some programs with local high schools, but if you mean is there a high school you could go to which would improve your chances of getting into Dartmouth upon graduation because of some special relationship, the answer is no. Obviously, those who go to top prep schools get into Dartmouth at greater rates than those from lesser schools, as is true at all top schools, but this is because those schools specialize in turning out students who are better-prepared, not because they have a special relationship with particular schools.
No.
Dartmouth has summer programs for high school students, and they may be engaged in some programs with local high schools, but if you mean is there a high school you could go to which would improve your chances of getting into Dartmouth upon graduation because of some special relationship, the answer is no. Obviously, those who go to top prep schools get into Dartmouth at greater rates than those from lesser schools, as is true at all top schools, but this is because those schools specialize in turning out students who are better-prepared, not because they have a special relationship with particular schools.