The Tip
It does not have an official name, but it is the tip of Cape York Peninsula.
The northernmost tip of mainland Australia is Cape York. It is located on Cape York Peninsula, in Queensland.
Queensland's most northerly point is Cape York, on the tip of Cape York Peninsula.
The Cape Peninsula
Cape York Peninsula is the northernmost peninsula of Australia, located on the eastern side of the continent. It is part of the state of Queensland, and positioned north of 16°S latitude. It includes an area of about 137,000 km². At its widest point, it is 430 km from Bloomfield River in its southeast, across to the western side, just south of Kowanyama. North to south, it is about 660 km from the southern border of Cook Shire to the tip, which was named Cape York by Captain Cook in 1770.
On the mainland it would be Seisia just north of Bamaga on Cape York Peninsula. Alternatively, it would be Thursday Island, a small island community just off the tip of Cape York.
Cape Colville.
cape colville
The cuscus is native to northeastern Australia (the tip of Cape York Peninsula) and the island of New Guinea. It lives in lowland tropical rainforests, mangroves, hardwood and eucalypt forests.
There are many islands directly north of Cape York Peninsula and, it would depend on which part of the tip of Cape York Peninsula you are looking from and, what you define as an island. The two nearest islands from the sign-posted "tip" of Cape York Peninsula (the northern most point of the Australian mainland) would be York Island followed by Eborac Island, both within swimming distance if you can beat the sharks, the crocodiles and the tide, but these are little more than rocky outcrops. The nearest relatively large and inhabited islands would be Prince of Wales Island, then Horn Island, then the most well known island would be Thursday Island, a little further on again.
cape colville (p.s ignore the advertisements)
The distance between the tip of Australia (Cape York Peninsula) and the bottom of Tasmania is around 3700km.