Chávez is known as the father of the farm labor movement in the 1960s, and fought for better working conditions, especially for Latino farm workers and their families.
"Our world is a better place because César Chávez decided to change it. Let us honor his memory, but most importantly, let us live up to his example. Sí, se puede. Sí, se puede. Sí, se puede," Obama said of Chávez at Nuestra Señora Reina de la Paz - Our Lady Queen of Peace - in Keene, California.
The opening of the monument comes just shy of a month before the presidential election, and both Obama and Republican challenger Mitt Romney have sought out opportunities to cater to Latinos.
Obama acknowledged during his brief remarks at La Paz that Latinos have a higher than average unemployment rate - the Latino unemployment rate is nearly 10 percent compared to a national average of just below eight percent - and said Chávez fought for farm workers even in the face of adversity.
He called the story of the movement "a story of determined, fearless, hopeful people who have been willing to devote their lives to making the country a little more just and a little more fair."
“Cesar Chavez gave a voice to poor and disenfranchised workers everywhere,” said President Obama. “La Paz was at the center of some of the most significant civil rights moments in our nation’s history, and by designating it a national monument, Chavez’s legacy will be preserved and shared to inspire generations to come.”
Chávez passed away in 1993, but Dolores Huerta, with whom he founded the National Farm Workers Association, now the United Farm Workers, attended the ceremony along with Chávez' wife Helen, who continues to live on the property.
"Today, Helen, we are your guests," the president said, "and you should feel free to kick us out whenever you want."
La Paz also continues to serve as the United Farm Workers of America headquarters. Obama declared 105 acres of the La Paz property a national monument that will be managed by the National Park Service. It is the 398th unit of the national park system.
"Every time somebody's son or daughter comes and learns about the history of this monument, I want them to know that our journey is never hopeless; our work is never done," Obama said.
Obama recalled Chávez' boyhood, including the fact he attended some 65 elementary schools as he followed the crop cycle.
His son and president of the César Chávez Foundation, Paul Chávez, who spoke before Obama, said La Paz became "a spiritual harbor" for his father, a respite from the tough campaigns he fought in the fields and cities across the country.
"Now the story of César Chávez and the contributions of those thousands of Latinos and immigrants who joined 'La Causa' will be shared with Americans," he said.
In addition to members of the Chávez family, Labor Secretary Hilda Solis and Interior Secretary Ken Salazar where on hand for the event.
"Today, La Paz is enshrined as a place where civll rights for millions of Latino families was born," Solis said.
"Once social justice change begins, it cannot be reversed. You cannot uneducate the person who has learned to read," she recalled Chávez saying.
While the trip to Keene, Calif., to pay tribute to the founder of the United Farm Workers was technically official White House business, it also helped magnify Obama's outreach efforts to the Hispanic community. It is an important voting bloc whose turnout could be crucial to his chances in the battleground states of Colorado, Florida, New Mexico, Nevada, North Carolina and Virginia.
Obama noted Chávez led a historic 300-mile farmworkers' march from Delano to the California state capitol in Sacramento and remembered Chávez's role in organizing a 1966 boycott of table grapes, which eventually drew 17 million supporters across the country and led to growers agreeing to among farm worker contracts in history.
The president also celebrated Chávez as a leader who strove to improve the lives of the next generation, a goal that Obama acknowledged the nation is currently struggling to achieve.
"Today, we have more work to do to fulfill that promise," Obama said. "The recession we're fighting our way back from is still taking a toll, especially in Latino communities, which already faced higher unemployment and poverty rates."
Before addressing thousands at the site of the national monument, Obama toured the grounds of La Paz, where Chávez is buried, and met privately with the late leader's wife, Helen Chávez and his son, Paul.
And while Obama didn't expressly ask for votes, others who spoke before the president at Monday's ceremony reminded voters that Obama has appointed two Latinos to Cabinet positions — Labor Secretary Hilda Solis and Interior Secretary Ken Salazar — as well as the first Latina Supreme Court justice, Sonia Sotomayor. And they brought up the president's decision to defer deportation of young illegal immigrants who join the military or attend college.
The president was greeted with chants of "Four more years" by the friendly crowd. Obama derived his iconic 2008 slogan "Yes we can" from Chávez, who coined the phrase "Si se puede" during his efforts organizing migrant workers in the 1960s and 1970s.
Obama, who won the Latino vote by a better than 2-to-1 margin in 2008 over Sen. John McCain, is ahead of Romney nationally among that group 72%-to-21%, according polls published Monday.
Matt Barreto, a pollster with Latino Decisions, said what remains to be seen is whether Obama can turn out Hispanic voters at levels that could help him over the hump in critical swing states. Honoring Chávez is a smart move toward reminding voters of his record on issues important to the Hispanic community, he added.
Results of polling in three battleground states, Florida, New Mexico and Virginia, show Obama and Romney are closer in the race for the Latino voters.
The two candidates are knotted at 47%-47% among Hispanics in Florida, while Obama holds a 58-26% edge in New Mexico and a 57%-42% lead in Virginia, according to polls conducted by Public Policy Polling on behalf of the left-leaning Natural Resources Defense Council Action Fund and published Monday. Obama holds a 71%-20% lead among Hispanic voters in Nevada, another important state both candidates are vying for.