Fillenwarth Beach was started by Arthur T. (A.T.) Fillenwarth and his wife Sadie. Arthur was a lawyer in Sanborn, Iowa. In 1919, he purchased land in Arnolds Park and built a cottage for his family. The cottage was simple. It had no windows, but awnings and screens covered the openings. It was named "Old Faithful".
One day a man came by and offered to rent this cottage for a week. A.T. couldn't refuse the offer and so he and his family moved back to Sanborn for the week. Several more offers to rent his cottage followed, and A.T. decided he needed to build more cottages for rental purposes so he and his family could enjoy staying at Okoboji.
In the early twenties, A.T. built 7 cottages for rent. All were summer cottages with glass windows. A.T. realized that rental demand for his cottages was there, and built 12 lake bank cottages below his first 6 rental cottages. A.T. also acquired other cottages so that by 1930, he had 36 cottages.
Sadie Fillenwarth did the resort's laundry, handled the reservations, and acted as receptionist. A.T. and Sadie had 3 children. Faith, who died of scarlet fever at age 7, Joy, who died shortly after birth, and Kenneth, who was born in 1924.
From his early teens, Ken helped build docks, make repairs, and show units to prospective guests. Ken also gave guests boat rides in his row boat equipped with an outboard motor. In his later teens, Ken enjoyed teaching guests to ski (and driving pretty girls around in his Chris Craft.)
One of Ken's best friends was S.J. Brownlee. The two of them often went to the amusement park in the evening and afterward to Red's Restaurant for a hamburger and "money orders" (french fries). They kept their own bottle of ketchup at Red's.
Ken was drafted into the Army in 1944, and after combat duty in Germany and occupation in Japan, he returned to pursue his college education at the University of Iowa. Ken continued to help A.T. with the cottage business in the summertime.
While he was in law school at the University of Iowa, Ken met his wife Ruth, whom he married in April, 1950.
Ruth had set up her own law practice in Estherville and Ken joined the practice in May, 1950. He continued to assist his father in running the resort.
Ruth and Ken had two daughters. Lynn, born on July 4, 1951 and Julie, born on October 3, 1953. Lynn and Julie were both expected to assist with various cottage business duties, appropriate to their age.
In 1964, the present Fillenwarth Beach office construction began. Unfortunately, Sadie Fillenwarth died in December, 1964 and never saw it. The new building was completed in the spring of 1966.
On June 13, 1968 Fillenwarth Beach was struck by a tornado, which demolished most of the rental cottages on the main beach. It left only the newly constructed office building and the original cottage, "Old Faithful", standing with only minor damage. In the fall of 1968, construction began on the present large chateau building on the main beach, and it was ready for occupancy in the spring of 1969.
A.T. Fillenwarth died in December, 1971.
Fillenwarth Beach saw substantial growth in the 70's. First, the present Fillenwarth South Beach was acquired in 1974 after purchase of the former Parkview Motel. The Cottage Colony was added in 1978 after acquisition of Gateswood Resort. Also during this time, Old Faithful was converted into the indoor pool at the Main Beach.
Another major change was the rebuilding of the sea wall at the Main beach in 1998, to replace the wall built in 1938. In the old wall's place is the Seawalk which has lounges for sunning and for viewing the beautiful sunsets and gas grills for family barbecues.
The Sun Runner boats have become a familiar image on West Lake Okoboji. With sun-drenched decks and complimentary beverages, they have also become a favorite among guests. Sun Runner I was custom built for Fillenwarth Beach in 1989. The Kenner Boat Works of Knoxville, Arkansas built the boat after the Fillenwarths came down to Arkansas and test drove the Boat Works own boat, Suwannee and made suggestions on how the boat could be better made to accommodate guests. Sun Runner I was then brought to Okoboji and christened. After an electrical fire aboard Sun Runner I while it was in its hoist in 1992, Suwannee made the long trip north and became Sun Runner II. Starting in 1993, both boats were operating daily, cruising around West Lake Okoboji. Because of the record flooding that year, there was a no wake zone around the Okobojis and the Sun Runner cruises became social events on a eerily quiet lake. The Sun Runner cruises continue to be an integral part of many of Fillenwarth's guests summer itinerary, as do the ski boats, sailboat, and Sea Ray cruise rides.
The resort continues to change, with yearly remodeling and construction of units. Some examples include units 155 & 156, which were added in 1992, and 412, 413, and 414, which were completely rebuilt in 1999.
The Fillenwarths have seen many changes in the resort business. Gone are simple summer cottages with the promise that they were "air conditioned by God." Replacing them are upgraded accommodations with air conditioning and other modern amenities, and an updated emphasis on guest services that will continue to make Fillenwarth Beach a family favorite for years to come.