If today's land value were taken into consideration, Catherine's estate would be worth well over $1 billion. Not too shabby for an Irish lass who immigrated virtually penniless to the New World. What's more, through her charitable contributions, Catherine Dunne definitely left her mark in the South Valley.

That's why she's the fourth and final individual portrayed in this March-long series of columns celebrating local ladies during Women's History Month.

Catherine was born in Wexford County, Ireland, in 1831 to John and Mary O'Toole. Like many Irish of that era, the family immigrated to Quebec, Canada, while Catherine was still a young girl.

There, she received a solid Catholic school education and grew up to be a fine young lady.

At age 19, Catherine's life story took a major turn when Quebec citizen Patrick Fitzgerald died, leaving his wife Johanna to care for six young children.

Johanna happened to be the daughter of South Valley pioneer Martin Murphy, Sr., (part of the first wagon team to traverse the Sierra Nevada to California).

Concerned about his daughter and grandchildren, Murphy asked his son Bernard to go to Canada to fetch Johanna and her brood and bring them to the South Valley.

But the quiet Bernard also had another motive in making the arduous trip. He wanted to reacquaint himself with and marry a certain young woman he'd fallen in love with back when he had resided in Quebec.

In 1851, Bernard made the long voyage from San Francisco to Quebec. But arriving in that Canadian city, he felt crushed to learn his love had given up on the prospect of his ever returning. She'd wed another.

Somehow, fate brought Bernard and Catherine O'Toole together. The Irishman felt deeply attracted to the friendly young woman. They married, and she joined the Murphy clan in traveling to California via the tropical jungle trails of the Isthmus of Panama.

The couple settled on Bernard's 4,000-acre Rancho La Polka near what is now Gilroy. They lived in a tin house that Bernard had earlier had shipped around the Cape Horn of South America. Here, Catherine gave birth to a son they named Martin J.C. Murphy after Bernard's father.

Tragedy, however, struck the happy family on April 11, 1853. On that date, Bernard took a business trip on the steamboat Jenny Lind from the South Bay port town of Alviso to San Francisco.

Around noon near what's now the San Mateo Bridge, the ship's boilers exploded. Scalded severely, Bernard was one of many passengers who died an agonizing death that day.

The widowed Catherine inherited Bernard's vast ranch estates. Over about a decade-long period, she prudently managed the various tracts of land by herself while also raising her young son.

One day while visiting San Francisco, Catherine happened to meet a handsome man named James Dunne. He was a prominent Irish mercantile businessman who had journeyed to California from New Orleans.

Dunne had invested his money wisely in various large rural properties in the South Valley area. This included the San Felipe Ranch in what's now San Benito County territory just north of Hollister. He also owned a large ranch in the King City area.

Catherine married James Dunne on May 6, 1862. Together they had three children and named them Mary, Peter and Kate.

When James died on June 4, 1874, Catherine found herself once again managing an immense estate - this time a combination of ranch land property that once belonged to her two deceased husbands. As well as other extensive holdings elsewhere, she controlled more than 18,000 acres of valley and hill land dotted by oaks and criss-crossed by creeks in the area that later became known as Morgan Hill.

Over the late decades of the 19th century, more farmers moved into the South Valley region. A railroad line connected the burgeoning community to San Jose and San Francisco. Small farm houses and windmills started filling the valley.

The wealthy and socially-active Catherine decided to give back to the region. She donated 17 acres of Gilroy land for the St. Mary Church and parish. Part of this property was set aside for a cemetery as well as a Catholic school.

In 1895, Catherine's son Peter took over managing the family property and ranch business. Four years later, he hired the San Jose real estate firm of Burbank & Devendorf to sell subdivided lots of land in the shadow of El Toro's peak.

Fancy promotional literature captured in black-and-white photos the Eden-like serenity of the "Catherine Dunne Ranch." Real estate lots sold for between $25 and $125 per acre depending on prime location. (Today, most South Valley families pay more than that each week for groceries.)

With sales of the lots, more and more people began moving into the area. The small farming village of Morgan Hill sprang up along the railroad track.

With an eye to the religious benefit of the town, Catherine donated property to establish a Catholic church in the new town. It was called St. Catherine's after her patron saint.

And Dunne Avenue, a major country lane leading east from downtown Morgan Hill to the Henry Coe Ranch, was named after the charitable Catherine herself.

Today, it is a busy thoroughfare edged by a gauntlet of neighborhoods and shopping centers.

Catherine died at the age of 96 on March 10, 1925, in the Santa Barbara home of one of her daughters. Many of her descendants still live in the South Valley region.

Take a look at the photograph of Catherine illustrating this column, and you'll see in her eyes a deep kindness and compassion. You'll see the woman genuinely cared about people. Catherine O'Toole Murphy Dunne was a true pioneer of the South Valley region. Through her charitable deeds, she definitely left her mark on history here.

Martin Cheek Marty Cheek is the author of 'The Silicon Valley Handbook.' His column appears every other Friday. You can reach him by email.