Christian August of Holstein-Gottorp, Prince of Eutin
Christian August of Holstein-Gottorp-Eutin (11 January 1673 – 24 April 1726) was a cadet of the reigning ducal House of Holstein-Gottorp who became prince of Eutin, prince-bishop of Lübeck and regent of the Duchy of Holstein-Gottorp.
He was the father of Adolf Frederick, King of Sweden, and the maternal grandfather of Catherine the Great, Empress of Russia.
John Adolf, Duke of Holstein-Gottorp
Johann Adolf of Holstein- Gottorp( 27 February 1575 – 31 March 1616) was a Duke of Holstein- Gottorp.
Christine of Hesse
Christine of Hesse (29 June 1543 – 13 May 1604) was Duchess consort of Holstein-Gottorp as the spouse of Duke Adolf of Holstein-Gottorp.
She exerted some political influence as a widow after 1586.
Claes Adolph Fleming
Count Claes Adolph Fleming( 1771- 1831) was a Swedish court official and diplomat, and member of the Swedish Academy.
He was the one of very few personal friends and confidants of king Gustav IV Adolf of Sweden, and according to Hedvig Elisabeth Charlotte of Holstein- Gottorp he was often courted by petitioners, but normally refused to make use of his influence.
He was given numerous diplomatic missions by the king, and accompanied him to Saint Petersburg in 1796.
Adolf, Duke of Holstein-Gottorp
Adolf of Denmark or Adolf of Holstein-Gottorp (25 January 1526 – 1 October 1586) was the first Duke of Holstein-Gottorp from the line of Holstein-Gottorp of the House of Oldenburg.
He was the third son of King Frederick I of Denmark and his second wife, Sophie of Pomerania.
King Frederick I had his son educated by Philip I, Landgrave of Hesse.
He spent four years at the Landgrave's castle in Kassel.
In 1544, Adolf, his brother Johann, and their half-brother King Christian III of Denmark, divided the duchies of Schleswig and Holstein.
The areas were divided according to approximately equal tax proceeds.
Adolf, as the youngest, was entitled the first choice.
Since he selected the part with the castle Gottorp, the line of the house Oldenburg created by him was called "Schleswig-Holstein-Gottorp".
Princess Ulrike Friederike Wilhelmine of Hesse-Kassel
Princess Ulrike Friederike Wilhelmine of Hesse-Kassel  (31 October 1722, Kassel – 28 February 1787, Eutin) was a member of the House of Hesse-Kassel by birth, and of the House of Holstein-Gottorp through her marriage to Frederick Augustus
I, Duke of Oldenburg.
Ulrike was the Duchess consort of Oldenburg from 1774 until her husband's death on 6 July 1785.
Charlotte Stierneld
Christina Charlotta "Charlotte" Stierneld née "Gyldenstolpe" (1766-1825) was a Swedish courtier; governess for the royal children in 1802-1809, and "överhovmästarinna" (Mistress of the Robes) to the queen of Sweden, Hedvig Elisabeth Charlotte of Holstein-Gottorp, from 1811 to 1818.
Hedvig Elisabeth Charlotte of Holstein-Gottorp
Hedwig Elisabeth Charlotte of Holstein-Gottorp (22 March 1759 – 20 June 1818) was Queen of Sweden and Norway as the wife of King Charles XIII and II.
She was also a famed diarist, memoirist and wit.
She is generally known in Sweden by her full pen name in Swedish (above), though her official name as queen was Charlotta.
She was born in Eutin the daughter of Duke Frederick August
I of Holstein-Gottorp and Princess Ulrike Friederike Wilhelmine of Hesse-Kassel.
She grew up in Eutin and married her cousin Charles, Duke of Södermanland, in Stockholm on 7 July 1774 when she was fifteen years old.
The marriage was arranged by King Gustav III to provide the throne of Sweden with an heir.
The King had not consummated his marriage and had decided to give the task of providing an heir to the throne to his brother.
Frederick II, Duke of Holstein-Gottorp
Frederick II, Duke of Holstein- Gottorp( 21 April 1568 – 15 June 1587) was a Danish- German nobleman.
He was the eldest son of Duke Adolf of Holstein- Gottorp and his wife, Christine of Hesse( 1543- 1604).
He inherited the ducal share of rule in the royal Danish- ducal condominium of the duchies of Holstein and of Schleswig when his father died in 1586, and died only a year later.
Duchess Marie Elisabeth of Saxony
Duchess Marie Elisabeth of Saxony (22 November 1610 – 24 October 1684) was duchess consort of Holstein-Gottorp as the spouse of Duke Friedrich III of Holstein-Gottorp.

Question: Which country Hedvig Elisabeth Charlotte Of Holstein-Gottorp's mother is from?
Answer: Oldenburg