They placed bouquets outside the mortuary where Charlie Kirk’s body lay. They drove by his church. They formed prayer circles and snapped somber photos at a sprawling memorial outside the headquarters of his conservative political group.

As tens of thousands of people poured into Phoenix this weekend to attend Mr. Kirk’s memorial service at the city’s N.F.L. stadium on Sunday, they turned the sunbaked streets into a kind of sprawling pilgrimage to commemorate the conservative activist in his adoptive home state, where conservatives are now fighting to roll back Democratic wins in statewide offices in recent years.

“I just felt called to come,” said Cate Cara, 54, who flew to Arizona from her home in Boca Raton, Fla., with the hope of joining the more than 100,000 people planning to attend the memorial service for Mr. Kirk at a sprawling sports complex in suburban Phoenix.

Ms. Cara was planning to line up hours in advance to get a seat at the first-come, first-served service, but first, she stopped on Saturday morning at the front gates of Turning Point USA, the conservative youth organizing group Mr. Kirk founded.

She placed a sign honoring Mr. Kirk among the wilting flowers, faded notes and scribbled prayers of a tribute that has grown to the length of a city block in the 10 days since Mr. Kirk was fatally shot while speaking at a Utah college.

“He built this, here,” Ms. Cara said. “I just wanted to be around it, and feel it.”