9BabyNames Baby names with meanings & US popularity data

Declan vs William

How Declan and William compare across 146 years of US Social Security Administration baby-name records — popularity history, peak years, current rank, and which name overtook which.

Open Name Tournament

Declan

Male · Irish

Meaning: The Name Of An Irish Saint.

William

Male · German

Meaning: Resolute Protector: Will. For A Long Time After The Norman Conquest In A.D. 1066 Many English Boys Were Given Some Form Of William The Conquer's Name. William. The Firstborn Son Of Prince Charles Is Named William.

US Popularity History — Side-by-Side

Annual US births named Declan (boys) vs William (boys), from US Social Security Administration national records.

Source: US Social Security Administration. Names appearing fewer than 5 times per year are suppressed by SSA.

Quick Stats

Metric Declan William
Peak year (most US births) 2019 — 3,971 boys 1947 — 67,001 boys
Peak rank #95 #4
Most recent rank (2025) #139 (2,570 births) #9 (10,545 births)
Total US births since 1880 57,105 4,199,549
Last 10 years (2016–2025) 33,607 127,126

Peak comparison takeaway

At its all-time peak, William reached 67,001 US births in 1947 — 63,030 more than Declan's peak count.

Strongest States — Last 10 Years

States where each name ranked highest, from SSA's state-level dataset. Lower average rank = name appears closer to the top of that state's boys-name list.

Declan — top 5 states

#StateAvg rankBirths
1 New Hampshire #51 239
2 Montana #53 172
3 Idaho #56 318
4 Maine #59 192
5 Massachusetts #61 1,001

William — top 5 states

#StateAvg rankBirths
1 Alabama #1 3,254
2 South Carolina #2 2,682
3 Mississippi #2 1,586
4 Tennessee #2 4,126
5 Georgia #2 5,159

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Data & methodology

Source: US Social Security Administration national baby names dataset 1880–2025 (CC0 public domain). Names with fewer than 5 occurrences in a given year are suppressed by SSA. State-level coverage runs 1910–2025. Crossover detection compares annual birth counts (not ranks) for each year both names appear. Methodology: see full notes. More comparisons →