This is now the Russian enclave of Kaliningrad, not to be confused with present-day Königsberg in Germany.
The overlays that highlight 17th century London features are approximate and derived from Wenceslaus Hollar’s maps:
Open location in Google Maps: 54.654769, 20.346679
cumgranosalis • Link
todays drop in on the Baltic and see the ice.
Chart showing the number of references in each month of the diary’s entries.