Well 1 was definitely the "pig war" that happened in the late 1850s. https://en.wikipedia.org/wiki/Pig_War_(1859)

It started over a dispute about a poor American farmer shooting a rich British farmers pig who escaped its pen and was eating all the poor farmers crops. Also despite being a war it was mainly posturing by both sides, I don't think either side actually ended up shooting at each other. Instead they just kept making ramparts and barricades all over the place and then stared at each other across from them.