Within minutes of the two explosions at the Boston Marathon finish line, cities across the county were placed on high alert.
In New York, BuzzFeed.com reporter Ryan Broderick said the response was almost immediate.
"There's definitely kind of a sense New York is top of this trying to make people feel safe and secure," said Broderick.
The response was more subdued on Oahu, but Honolulu police began more frequent checks of facilities and locations that could be considered targets.
The Department of Public Safety, the agency in charge of state sheriffs, said it "would work with law enforcement partners, both county and federal, to decide if any other security measures are needed..."
"You know the public sees uniformed law enforcement officers, but a lot goes into protective countermeasures," said Roger Strecker with the Intercept Investigative Agency.
Strecker is a threat assessment expert for the Department of Homeland Security and a former Honolulu Police Department officer.
Although the HPD has an Anti-Terrorism Intelligence Unit and, just last year, created a Major Events Division, Strecker says it's up to all of us to take notice of anything unusual -- what he calls "situational awareness."
"I think government's posture of 'if you see something, say something' really needs to resonate to the entire United States," said Strecker.
Meanwhile, Hawaii residents like Chris Benjamin, who ran in Monday's Boston Marathon are already pondering how this latest attack on American soil could change us.
"I think ever since 9/11 we're sort of known these kinds of things are possible, but I'm afraid it will change the character of events like this," said Benjamin.
Honolulu's Emergency Medical Services Division added it has the equipment and training to respond to an attack like we saw on Monday.