According to the 1898 publication Sonoma County Homes and Industries by Reynolds & Proctor, Dr. O'Donnell arrived in Glen Ellen in 1891. In addition to establishing the brickworks with Joshua Chauvet, he developed an extensive resort along Sonoma Creek. Quoting at length from Reynolds & Proctor:
Mineral Springs and Resort. This place is owned by Dr. C. C. O’Donnell, of 1206 Market Street, San Francisco, who acquired it seven years ago, and during that time he has quietly, but energetically, been developing the great Coal mine, which will do much for our state. Too much credit cannot be given Dr. O’Donnell for this enterprise as not only has he developed this immense coal deposit, but he has created one of the finest resorts on the coast. At Glen Ellen there are fine mineral springs which have proved by analysis to be the greatest remedy for liver, stomach and bladder complaints, rheumatism, catarrh and lung troubles. These springs are forty-six miles from San Francisco, to which there are four daily trains, via S. F. & N. P. R. R. Company.
Realizing what the utilizing of these springs will do for mankind, Dr. O’Donnell has expended large sums of money in laying out the grounds, making roads, building cottages, etc. The cottages have from three to ten rooms. They are all named. As you cross the bridge going to O’Donnell Avenue the first cottage you arrive at is “Golden Gate,” overlooking the entrance, the next is “Buena Vista,” then you have “Maple Laurel” and “Sunshine.” The Congregational Church stands next on O’Donnell Avenue. The Doctor gave the lot and assisted in having a church built. Passing along the avenue we have more cottages, “Olive,” “Ravenswood,” “Ingleside,” “Riverview,” “Loreley,” “Inglenook,” “Oak Grove,” “Woodbine,” “Manzanita,” “Magnolia,” “Riverside,” “La Paloma,” “Rosemound,” “Ferndale,” “Golden West,” “Mountain Home,” “Annex,” “Tocaloma,” “Locust,” and “Castle Cozy,” Dr. O’Donnell’s summer home. The cottages are furnished.
Prices range from ten to thirty-five dollars. Everything is brought in by farmers in the way of fruit, vegetables, butter, eggs, chickens, etc., at very reasonable prices. Grocery stores, butcher, ice, everything a person needs, can be had in Glen Ellen. The climate is unsurpassed. Elegant bathing, fishing and game abundant, and here all those seeking rest and health, or pleasure, can find a spot that will meet their wants, and that at a cost which all can easily bear and in all an ideal summer and winter resort.