San Marcos San Marcos is a city located in the northern portion of San Diego County, California, USA. San Marcos is a total of 19,959 acres and 75% of that acreage is developed land. As of 2005, the city had a total population of 73,054, with a median age of 33. San Marcos borders Carlsbad, which offers an array of golfing and tennis.
San Marcos Real Estate Information The San Marcos area is experiencing a buyer’s market boom. The prior market where sellers could sell to the highest frantic bidder is long gone. Pricing is now determined by the market, and what a willing and able buyer is willing to pay. That buyer, in turn, may compete with other buyers to determine an equitable sales price.