ENIn the archives of the Sea Museum and Aquarium in Klaipeda, which was founded in Merseburg, East of Germany, there was a bundle of photocopies of documents from the secret state archive of Prussia’s cultural heritage. e museum’s creators in German museums and archives sought not only the drawings of the old Nerija fort, but also materials on the historical development of Klaipeda port and shipping. Due to the lack of time and limited possibilities, documents are copied in a snap and do not respect any consistency. In most cases, the pictures are taken selectively, not in a row, so the use of this material for more careful research is complicated. Nevertheless, copies of documents are of considerable value in the study of some speci c historical processes and periods: the construction of the Klaipeda castle from the 16th to the 17th century; Installation of Klaipeda port in the XVIII century; shipbuilding in the 18th century in the second half; maritime trade problems at the end of the 18th century; Curonian lagoon shipping; Navigation School activities in the 19th century; navigation on the Nemunas river, etc. Here we will try to present the documents of this collection, which (as the primary sources) are important for Klaipeda port navigation signs: the buoys marking the shipwreck (fairway), exploration of the system of bac kseat (wizards), illuminating signs (signal lights, lighthouses).