Wednesday night, this tiny, remote town was a picture of tranquility in the humid summer heat. The handful of people outdoors lined a small bridge, with fishing lines cast over the sides.

At sunrise today, 200 federal and local law enforcement agents surrounded Everglades City. They set up roadblocks on the only highway leading out of town, and patrol boats were posted to watch for anyone trying to escape by water.

The agents from the federal Drug Enforcement Administration and the Collier County Sheriff's Department had arrest warrants for 41 people suspected of running one of the country's major marijuana importing and distribution businesses.

Authorities said they expected by tonight to have rounded up close to 35 of the 41 people indicted, most of them from in or near this isolated community of 700 year-round residents, deep in the Everglades in southwest Florida.

One of those being sought was former Florida Supreme Court justice David McCain, according to law enforcement authorities.

Some still missing were local fishermen out on their shrimp boats, probably unaware of the indictments.

One federal agent called Everglades City--which has a significant segment of its population in jail or under indictment--"a town gone bad."

Sheriff Aubrey Rogers acknowledged that, although there are "many good people there," smuggling was so widespread that almost everyone "would have to have had some knowledge of what was going on."

DEA agent Frank Chellino said the investigation, called Operation Everglades, started two years ago when the sheriff came to the DEA and said that the drug problem in his area was too big for him to handle.

Even before today's raid, the DEA and the sheriff's office had arrested 153 people, about two-thirds of them South Americans seized on the high seas and about a third of them from the Everglades City area.

During the past two years authorities also seized more than 450,000 pounds of marijuana, worth about $179 million. They confiscated 39 boats, three airplanes and 21 vehicles.

Agents said that after today's arrests the government could seize 80 more boats, ranging in length from 20 to 80 feet. One agent joked, "When we try to sail them out of here, we're going to look like the Tall Ships."

Stanley Marcus, U.S. attorney for southern Florida, said DEA agents had infiltrated the town and acted as buyers, sellers and transporters in the marijuana business. He said the marijuana had come mainly from Colombia and Jamaica and had been distributed through Miami and up the East Coast.

Today's raid will not end Operation Everglades, Marcus said. The investigation in southwest Florida will continue into possible trafficking in cocaine and other major drugs under the Reagan administration's new crackdown on narcotics, he said.

Everglades City and nearby Chokoloskee Island--a small collection of trailer parks and modest one-story homes--are miles away from any civilization.

Surrounding them is a maze of rivers and canals running through cypress and mangrove swamps and large, open fields of grass. Alligators are common, and residents say that sea cows are still sighted occasionally.

There is no real business in Everglades City, except for the motels that come to life during the winter tourist season. The community has survived on its fishing industry: pompano in the summer, stone crab in the winter and some shrimping all year.

But authorities say that for many years the fishermen have been turning to drug trafficking because of its lure of quick and constant money.

Sheriff Rogers said the current drug investigation is not Everglades City's first brush with the law. During Prohibition in the 1930s, he said, some residents became renowned rumrunners, and direct descendants of those families were among the people arrested today.

Peter F. Gruden, special agent in charge of the Miami DEA office, called the Everglades City area a "smugglers' paradise." Besides the endless streams and canals through the swamps, the community is at the tip of an area known as the Ten Thousand Islands. Most of the islands are uninhabited and largely unpatroled.

Despite the terrain and the difficulty of infiltrating communities like Everglades City, Gruden said he was hopeful. As DEA agents at roadblocks searched cars of Everglades City residents, he said, some looked more relieved than angry.

"I think some people were upset about" drug-smuggling operations, he said. "I think people wanted to come forward, but until now they didn't know where to go."