Dennis Warren McCosker

Dennis Warren McCosker was born on November 23, 1938, in Oakland, California to his devoted parents Aileen Constance and Alfred John McCosker. Surrounded by his loving family, Dennis was called back to God at the age of 86, on February 18, 2025, at the Ranch in Chico, California. Dennis was raised in Oakland, California with one older brother and two younger brothers.   

Dennis attended Piedmont High School, graduating in 1956, and went on to attend the University of Santa Clara where in 1960 he received a bachelor's degree in business.   

He joined the United States Army Corps of Engineers in 1961 to 1967 where he was known to his comrades as Mack. He did basic training at Camp Roberts, and to his mother and father’s relief, was stationed nearby at Fort Baker.  He moved out to the family's Canyon Ranch while in the Army. He loved the land and was deeply connected to the ranch through his father.  

On November 7, 1964, he married Kathleen Marron and in December of 1965 they welcomed their first child Margaret followed by five more. They were blessed to spend 45 beautiful years together on the Canyon Ranch where they built a home and raised their five daughters and one son.  Besides faith, family and Kathleen, the Canyon Ranch was his true love. 

In 2010, Kathleen and Dennis moved to Chico, CA, where they spent 15 special years close to family. While in Chico, Dennis created more memories and continued to get into plenty of mischief.   

Denny faithfully attended daily Catholic Mass as often as he was able. For most of his life, he could be found at school and sporting events for his children and then the grandchildren.  He spent many hours sitting in his pickup listening to classic country radio while waiting for a school bell to ring or practice to finish.   

He loved horses, cattle, dogs, and ranch life.  He was always quick to lend a hand to the neighboring ranchers. Often on Thursdays and Fridays, he was found at the Auction yard in Orland or Cottonwood.  

He worked as a heavy equipment operator for his father’s construction business, Independent Construction, with the Operating Engineers 3. Every year he looked forward to blading the University Fire Trails in the Berkeley hills.  

For many years, he welcomed memorable gatherings at the Ranch House which included family holidays, 4th of July, seasonal black berry picking, and of course the barbecues for the Serra and 50/50 Clubs. He was also a proud member of the Alameda County Mounted Sheriff’s Posse.  

His favorite hobby included taking a short-cut to find the best donut or ice cream shop, and then sharing with friends, old and new. He was quick with a joke and a smile. 

Dennis was preceded in death by his Parents, Daughter Margaret (Ray), and Grandson Jess.  Papa Dennis is survived by his wife Kathleen and children Sheila Nichols (Thomas); Anna Enneking (Thomas); Carolyn McCosker; Patrick McCosker (Allison); Evelyn Hogan (Will); the AFS exchange students: Eva, Cathie, Dario, Jean-Marie, as well as, his 14 grandchildren, 2 great-grandsons, with a 3rd due to be born in a couple of weeks. 

Services will be held on Tuesday, February 25, 2025, at Our Divine Savior Catholic Church 566 E. Lassen Ave, Chico, California, 95973.The Rosary will begin at 10:30 AM followed by Mass at 11:00AM. Please join the family for a reception in the Church Hall immediately following the Mass. 

The burial will be at 11:00 AM on Wednesday February 26, 2025, at Glenn Oaks Cemetery 11115 Midway, Chico, California, 95928. 

In lieu of flowers, donations may be made to Enloe Hospice or Catholic Charities.