Charles Sumner was an American politician and senator from Massachusetts. He was a fierce supporter of the equal rights movement and his anti-slavery speeches ensured that he had very few friends within the Senate. In fact, one of his opponents wanted to challenge him to a duel but was advised that "since Sumner was no gentleman, it would be more appropriate to beat him with his cane". So this opponent took the advice to heart. Brandishing a thick gutta-percha cane, he confronted Sumner at his desk and proceeded to beat him to death with it.
I'm not sure if this road is named after Charles Sumner. When searching for this cache, keep in mind what weapon was used to murder this hero. You're hunting for a homemade container that somewhat stands out in the environment. Stay away from the electrical box because it's not on it. BYOP.