Question: the northern portion of Curonian Spit National Park lies within a country in the Baltic region of northern-eastern Europe that is bordered to the north by what?

Context articles: Curonian Spit National Park (Lithuania)
Smiltynė
Florida Reef
Prussia (region)
Curonian Spit National Park
Lithuania
Geography of Lithuania
Curonian Spit
Curonian Spit National Park (Russia)
Curonians

Kuršių Nerija National Park is one of the five national parks in Lithuania.
 It was established in 1991 to protect the unique ecosystems of the Curonian Spit and Curonian Lagoon.
Smiltynė (German: "Sandkrug" ) is a part of Klaipėda city municipality in Lithuania.
 It is located on the northern tip of the Curonian Spit, next to a narrow strait which connects the Curonian Lagoon to the Baltic Sea.
 Across the 0.5 km strait, on the Lithuanian mainland, is the port city of Klaipėda.
 Ferries transport vehicles and people daily between the two cities across the strait, as there is no connecting bridge.
 Smiltynė serves as a public beach for Klaipėda residents, as ports take up the coastline around Klaipėda.
The Florida Reef (also known as the Great Florida Reef, Florida reefs, Florida Reef Tract and Florida Keys Reef Tract) is the only living coral barrier reef in the continental United States.
 It is the third largest coral barrier reef system in the world (after the Great Barrier Reef and Belize Barrier Reef).
 It lies a few miles seaward of the Florida Keys, is about 4 miles (6 to 7 km) wide and extends (along the 20 meter depth contour) 270 km from Fowey Rocks just east of Soldier Key to just south of the Marquesas Keys.
 The barrier reef tract forms a great arc, concentric with the Florida Keys, with the northern end, in Biscayne National Park, oriented north-south and the western end, south of the Marquesas Keys, oriented east-west.
 The rest of the reef outside Biscayne National Park lies within John Pennekamp Coral Reef State Park and the Florida Keys National Marine Sanctuary.
 Isolated coral patch reefs occur northward from Biscayne National Park as far as Stuart, in Martin County.
 Coral reefs are also found in Dry Tortugas National Park west of the Marquesas Keys.
 There are more than 6,000 individual reefs in the system.
 The reefs are 5,000 to 7,000 years old, having developed since sea levels rose following the Wisconsinan glaciation.
Prussia (Old Prussian: "Prūsa", German: "Preußen" , Lithuanian: "Prūsija" , Polish: "Prusy" ) is a historical region stretching from Gdańsk Bay to the end of Curonian Spit on the southeastern coast of the Baltic Sea, and extending inland as far as Masuria.
 The territory and inhabitants were described by Tacitus in Germania in AD 98, where Suebi, Goths and other Germanic people lived on both sides of the Vistula River, adjacent to Aesti (further east).
 About 800–900 years later the Aesti were named Old Prussians, who since AD 997 repeatedly successfully defended against take-over attempt by the newly created Duchy of the Polans.
 The territory of the Old Prussians and neighboring Couronians and Livonians was unified politically in the 1230s as the Teutonic Order State.
 Prussia was politically divided in the period 1466-1772, with western Prussia under protection of the crown of Poland-Lithuania and eastern Prussia a Polish fief until 1660.
 The unity of both parts of Prussia remained preserved by retaining its borders, citizenship and authonomy until western and eastern Prussia were also politically re-united under the Kingdom of Prussia.
 It is famous for many lakes, as well as forests and hills.
 Since the military conquest by the Soviet Army in 1945 and the expulsion of the inhabitants it divided between northern Poland (most of the Warmian-Masurian Voivodeship), Russia's Kaliningrad exclave, and southwestern Lithuania (Klaipėda Region).
 The former German state of Prussia (1701–1947) derived its name from the region.
Curonian Spit National Park might refer to one of the national parks on the Curonian Spit:
Lithuania ( , Lithuanian: "Lietuva" ] ), officially the Republic of Lithuania (Lithuanian: "Lietuvos Respublika" ), is a country in the Baltic region of northern-eastern Europe.
 One of the three Baltic states, it is situated along the southeastern shore of the Baltic Sea, to the east of Sweden and Denmark.
 It is bordered by Latvia to the north, Belarus to the east and south, Poland to the south, and Kaliningrad Oblast (a Russian exclave) to the southwest.
 Lithuania has an estimated population of 2.8 million people as of 2017 , and its capital and largest city is Vilnius.
 Lithuanians are a Baltic people.
 The official language, Lithuanian, along with Latvian, is one of only two living languages in the Baltic branch of the Indo-European language family.
Lithuania is a country in Northern Europe, most populous of the Baltic states, Lithuania has 262 km of coastline consisting of the continental coast and the "Curonian Spit" coast.
 Lithuania's major warm-water port of Klaipėda (Memel) lies at the narrow mouth of Curonian Lagoon, a shallow lagoon extending south to Kaliningrad and separated from the Baltic sea by Curonian Spit, where Kuršių Nerija National Park was established for its remarkable sand dunes.
The Curonian Spit (Lithuanian: "Kuršių nerija" ; Russian: "Ку́ршская коса́ (Kurshskaya kosa)" ; German: "Kurische Nehrung" ,    ; Latvian: "Kuršu kāpas" ) is a 98 km long, thin, curved sand-dune spit that separates the Curonian Lagoon from the Baltic Sea coast.
 Its southern portion lies within Kaliningrad Oblast, Russia and its northern within southwestern Lithuania.
 It is a UNESCO World Heritage Site shared by the two countries.
Curonian Spit National Park (Russian: Куршская коса ) (Also: Kurshskaya Kosa) covers the Russian-owned southern 41 km of the 98 km long, curved Curonian Spit – a type of depositional sandbar.
 The spit separates the salt-water Baltic Sea (on the west) from the freshwater Curonian Lagoon to the east.
 The southern portion of the spit lies within Zelenogradsky District in Kaliningrad Oblast, Russia; the northern portion lies within southwestern Lithuania.
 It is a UNESCO World Heritage Site shared by the two countries.
The Curonians or Kurs (Curonian: "Kursi"; German: "Kuren" ; Latvian: "kurši" ; Russian: курши ; Lithuanian: "kuršiai" ; Estonian: "kuralased" ; Polish: "Kurowie" ) were a Baltic tribe living on the shores of the Baltic Sea in what are now the western parts of Latvia and Lithuania from the 5th to the 16th centuries, when they merged with other Baltic tribes.
 They gave their name to the region of Courland ("Kurzeme"), and they spoke the Old Curonian language.
 Curonian lands were conquered by the Livonian Order in 1266 and they eventually merged with other Baltic tribes participating in the ethnogenesis of Lithuanians and Latvians.
 Direct descendants of the Curonians include the Kuršininkai of the Curonian Spit and the so-called Curonian Kings of Courland.