They don't agree.

The question asks for names, so the answer is a list. The most frequently cited witnesses are Holland and Bowers, with a handful of fellow railroad workers who also reported smoke or a puff near the fence. These accounts were given decades ago, and some were recalled or recorded differently over time. Smoke sightings are contested and are not accepted as proof of a shot from the knoll, because the official findings and later reviews point to other conclusions. Check the Warren Commission testimony and hearings for each person's exact words.

• Sam Holland watched from the Triple Underpass and told the Warren Commission he saw a puff of smoke under the trees by the fence.
• Lee Bowers was in the railroad tower behind the fence. He described a flash of light or smoke near the knoll area at the time of the shots.
• Other Triple Underpass workers, including Austin Miller, James Simmons, Richard Dodd and Frank Reilly, gave similar statements. I'm listing these from memory, and the exact wording of each account varies.
• Many other witnesses in the plaza did not report smoke, and some reported shots from other places.
• The Warren Commission found three shots fired from the Texas School Book Depository. The 1979 House Select Committee on Assassinations said a conspiracy was probable, based on acoustic evidence that a later National Academy of Sciences review discredited.

Holland, Dodd, and Simmons are the clearest names for the specific fence-area reports; Miller and Potter belong to the broader list of witnesses reporting smoke nearby. These are documented witness reports, not independent proof that the smoke came from a firearm. The House Select Committee’s photographic analysis found no puff of smoke or flash of light in the grassy-knoll photographs it examined.

• S. M. (Sam) Holland testified that he saw a puff of smoke emerge from beneath the trees on the knoll.
• Richard C. Dodd reported smoke coming from behind the hedge on the north side of the plaza.
• James L. Simmons described smoke toward the wooden fence in a later interview and discussed the sighting in his Clay Shaw trial testimony.
• Austin Lawrence Miller also reported what he thought was smoke or steam coming from trees north of Elm Street near the railroad tracks.
• Nolan Potter reported smoke rising from trees in front of the Depository, but did not precisely locate it at the fence.

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5. archives.gov
6. garyrevel.com
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8. jfk-assassination.net

During the November 22, 1963 assassination of President John F. Kennedy in Dallas, multiple spectators and railway employees watched the motorcade from the railroad overpass overlooking Dealey Plaza. When the gunshots occurred, several individuals observed what they described as a puff of smoke or vapor near the stockade fence and trees atop the grassy knoll. S. M. Holland provided the most detailed early account to the Warren Commission, and colleagues such as James Simmons and Richard Dodd gave corroborating interviews describing smoke in that location immediately following the gunfire.

• S. M. (Sam) Holland testified to the Warren Commission that he saw a 1.5- to 2-foot puff of smoke under the trees by the picket fence.
• James Leon Simmons reported seeing a puff of smoke come from under the trees directly in front of the wooden fence.
• Richard C. Dodd stated that he saw smoke emerge from behind the hedge and trees along the stockade fence.
• Austin L. Miller gave a sworn affidavit describing what appeared to be smoke or steam rising from the trees north of Elm Street.
• Other overpass and area witnesses describing smoke or steam included Walter Winborn, Thomas Murphy, Nolan Potter, and spectator Cheryl McKinnon.

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4. history-matters.com
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6. dokumen.pub
7. kenrahn.com
8. quora.com

This is a who-question, so the answer is a list rather than a yes or no. The names most consistently attached to 'smoke on the grassy knoll' are Sam M. Holland and Austin Miller, both railroad employees on the Triple Underpass with a clear view of the fence, whose Warren Commission testimony is the main source. Other names circulated later, but the accounts are inconsistent (smoke versus flash, differing times and vantage points), no one claimed to see a rifle fired from behind the fence, and what officers nearby reported was the smell of gunpowder. The evidence that these people made the reports is solid; the evidence for what they actually saw is not, so the overall picture is mixed.

• Sam M. Holland, a Union Terminal Railroad signal supervisor standing on the Triple Underpass, told the Warren Commission he saw a puff of smoke in the trees/fence area of the knoll after the shots (Warren Commission Hearings, Vol. 6).
• Austin Miller, another railroad worker on the overpass, also described seeing smoke or a flash near the knoll.
• Bystanders including Patricia Ann Lawrence, and in some later interviews Jean Hill and others, reported smoke on the knoll; these accounts came later and varied between tellings.
• Dallas police officers Joe Marshall Smith and Seymour Weitzman reported smelling gunpowder near the knoll rather than seeing smoke.
• The Warren Commission (1964) and the House Select Committee on Assassinations (1979) found no credible evidence that a shot was fired from behind the fence, and no witness saw a person firing there.

The question asks for the names of witnesses who saw smoke by the fence at the grassy knoll during the assassination of President John F. Kennedy. The official investigations, including the Warren Commission and the House Select Committee on Assassinations, did not document any credible witness who reported seeing smoke at that specific location. While some witnesses reported seeing or smelling smoke in Dealey Plaza, none are specifically tied to the fence at the grassy knoll. Claims about smoke at that location often rely on unnamed or anonymous sources, which are not considered credible evidence in official reports.

• The Warren Commission Report (1964) does not list any witness who saw smoke by the fence.
• The House Select Committee on Assassinations (1979) reviewed all witness statements and did not identify any who reported smoke at that location.
• No subsequent federal or credible independent investigation has documented a witness seeing smoke by the fence.
• Some witnesses reported seeing or smelling smoke in Dealey Plaza, but not specifically by the fence at the grassy knoll.
• Conspiracy theories often cite unnamed or anonymous sources for such claims.