The group of 40 people, mostly from the states of New York and New Jersey, arrived in Tel Aviv on Sunday before moving on to Gush Katif, the main Israeli settlement bloc in the Gaza Strip.
Their two-day solidarity visit was the brainchild of Dov Hikind, a member of the New York state assembly who has promised to bring "thousands" of American Jews to Gaza in July and August to obstruct the planned evacuation.
The controversial project will see the first ever withdrawal from Palestinian land since Israel occupied the West Bank and Gaza Strip in 1967.
Among the party are bankers, two state supreme court judges and doctors - both Democrats and Republicans. Each paid $1200 for the New York-Gaza return ticket.
Helen Friedman, 50, vowed to return in the summer with her family to organise "resistance", which she described as "civil disobedience".
"Our slogan is 'let our people stay'," the primary school teacher said, invoking the famous Biblical call of "let my people go", which Moses addressed to Pharaonic Egypt before leading the Jews across the Sinai.
"The land belongs to all the Jewish people and not only to Israelis," Friedman, head of the Americans for a Safe Israel organisation, added.
"The land belongs to all the Jewish people and not only to Israelis"
Americans for a Safe Israel
For 48 hours the activists will be carried in buses across the length and breadth of Gush Katif to meet as many of the 8000 settlers living in the occupied Palestinian territory as possible.
Shmuel Knopfler, a cousin of Dire Straits guitarist Mark Knopfler, launched a stinging diatribe against Israeli Defence Minister Shaul Mofaz for going ahead with the evacuation plan, which is likely to last five or six weeks.
"Forty days is the same time that it took the Nazis to liquidate the Warsaw ghetto" in 1943, the 50-year-old said.
Knopfler, though, refused to compare Sharon to a Nazi - a likeness that some ultra-nationalist Israelis have made. The Israeli leader is the recipient of dozens of death threats for his plan to end the Gaza occupation.
Instead, Knopfler talked about "il Duce Sharon", referring to Adolf Hitler's ally, Italian fascist dictator Benito Mussolini, for the prime minister's aim to clear Gaza of its Jewish residents.
Sharon has got dozens of death
threats for his Gaza pullout plan
The Americans then jumped back on their bus to go to a vegetable-processing plant close to the Mediterranean after pledging donations for a religious school in Neve Dekalim, the largest settlement in Gaza.
"We came to show solidarity. It will be the beginning of the end if we left," Denis Jakobowitch, 42, a New Jersey banker who made the trip after hearing about the visit on the radio, said.
It is estimated that there are around 400,000 Jewish settlers living on Palestinian land illegally captured during the 1967 Middle East war.