runescapeclassic
The main RuneScape Wiki has an article on: Crossbow
The Old School RuneScape Wiki also has an article on Crossbow.

A Crossbow is a ranged weapon that can be used at any level. It can fire both Crossbow bolts and Pearl bolts. It cannot be made using the Fletching skill. A Crossbow can be purchased at some archery stores and can be found at a spawn in Wilderness and Underground Pass graveyards. In RuneScape Classic there are only two types of crossbow, this and the Phoenix crossbow.

Item spawns

Location Number of spawns Number in stack
Level 25 Wilderness near the Boneyard 1

1

Dropped by

Monster Combat level Quantity Rarity
Hobgoblin 32, 48 1 3Uncommon
Zombie 24 1 3Uncommon