The Hobgoblin Peninsula is an area west of the Crafting Guild.
It is crawling with several level 30/35 Hobgoblins. On members servers, it spawns 3 snape grass in the sand pit near the end of the island. Some players gather the snape grass for a small profit, but since the peninsula is far away from a bank, this is not done by many players. The quickest way to get there is via the Skills Necklace teleport to the Crafting Guild.
Players can safely range or mage the Hobgoblins from the cow area beside it. However, they are suggested to cast telekinetic grab to get back their arrows or to retrieve loot. There's also a strange pile of sand in it, with an odd "look" option. Its use as of now is simply a place to gather sand. Players are able to use a bucket with the pile of sand to get a 'bucket of sand', material for glass-making. Since glass-making is part of the crafting skill, and the peninsula is very close to the crafting guild, it is possible that Jagex put this here with that in mind (though the purpose of the 'look' option on it is still a mystery). When a bucket is used on the pile it becomes smaller, and when a second is used it goes away completely, respawning a few seconds later.