Sen. Cory Gardner declined to say whether Congress should take actions to protect the probe, while Sen. Michael Bennet directly criticized President Donald Trump.
Kavanaugh was confirmed 50-48 Saturday. Every voting Republican backed the 53-year-old conservative judge.
In the past, the Conservation Fund had been a reliable stream of money for everything from building dog parks to adding pedestrian bridges.
The crowd chanted slogans like "Hell, no, Kavanaugh" and "No rejection, no reelection."
The letter to Sen. Cory Gardner’s office relates a two-decade old incident in which the writer claims her daughter witnessed Kavanaugh shove a woman he was dating.
Press Secretary Sanders said President Donald Trump "has said a number of times these individuals should be heard."
Political leaders of all stripes were united in praise of the senator and condolences for the McCain family when news of McCain's death was made public.
Sen. Michael Bennet has cosponsored, and Sen. Cory Gardner supports, a bill that could raise $6.5 billion for parks maintenance.
The bill would also require the State Department “to determine whether Russia merits the designation of a State Sponsor of Terror.