>I came across a set of Bolivian postage stamps from 1992 commemorating the
>establishment of and the raising of the Bolivian flag over
>"Boliviamar" and part of the harbor of Ilo, both in Peru. Boliviamar is a
>3 mile long recreation beach. The harbor provides otherwise
>landlocked Bolivia access to the Pacific. It's not clear to me if the
>territory comprising the beach is contiguous with the harbor or not.
>I've not been able to find a good map.

I have a 1964 1:200,000 map of Ilo, a small town in Southern Peru. I'd need
to know what the beach used to be called to determine how close it is to
Ilo town.

>While trying to find a map, I came across a Chilean map that shows that
>Peru possesses three pieces of land in the northern Chilean
>harbor of Arica. On these three pieces sit the town train station, a
>customs house and a large dockside warehouse on a mole in the harbor. An
>administrative map published by the Chilean foreign ministry marks off the
>pieces and shows them as not being under Chilean control. This has existed
>since June 3, 1929, as a result of the Treaty of Lima.

You'd need to check the treaty, which would be in the League of Nations
treaty series no doubt, held by any decent academic/law library.
I would strongly suspect that they were simply customs zones for
Bolivian/Peruvian imports/exports: bonded warehouses etc. I would consider
it most unlikely that they were true international enclaves.

Brendan