MINNEAPOLIS -- The 84-year-old king of Norway will have Thanksgiving Day dinner with a suburban family today as part of his sixth visit to a state with deep ties to his country.

"The king has a great affinity for his countrymen and really loves this area," said Liv Lyons, spokeswoman for the Sons of Norway, a cultural group in Minneapolis.

"He asked to come," said Ulf Christiansen, a Norwegian foreign affairs officer helping coordinate the event.

One Minnesotan in six, about 712,000 people, claimed some Norwegian ancestry in the 1980 census. Wisconsin had the next largest Norse population, with 391,000. The number is smaller but the proportion higher in North Dakota, where 184,000 people, or 30 percent, claimed some Norwegian ancestry. King Olav visited Minnesota twice while he was crown prince -- in 1939 and 1942. He became king 30 years ago and visited Minnesota in 1968, 1975 and 1982. His visit this year is unofficial, an extension of a state visit to Canada.

King Olav arrived in Minnesota earlier this week. He visited St. Olaf College in Northfield and was to return to the Twin Cities today for a private reception at Augsburg College and Thanksgiving dinner at the home of Lawrence O. Hauge in the affluent suburb of Edina.

The only public event planned for the king's stay is a dinner tomorrow at a Minneapolis hotel.

On Saturday, Olav will fly to Decorah, Iowa, to visit the Vesterheim Norwegian-American Museum. On Sunday he will fly to Washington. He will meet with President Reagan Monday before returning to Norway.