Curonian Spit played a key role in medieval transport for Teutonic Order in 13th – 16th C. It ought to be presented again, since last essays about this subject originate from before the Second World War. The given term ‘infrastructure’ should be explained as castles or hostels (German: nachtleger) and other important points of military activity and thus all problems that refer to their functionality. Those subjects cannot be properly described without referring to written administration sources. Also organization of the Church on Curonian Spit will be presented, as it will contribute greatly to final conclusions. This work does not cover Lithuanian achievements in this field of interest, with exclusion of Nijole Strakauskaites’ recent work about the Spit (2004), which however isn’t about this subject. It is not a widespread subject of scholarship nowadays and it is also hardly known in Poland. This article is also a leap to create a monograph about Curonian Lagoon and it’s similarities to Vistula Lagoon as well as Hel Peninsula in the future.