I took a look at the State of Pennsylvania website:
Does Pennsylvania have a gift tax?
Answer ID 378 | Published 12/03/2002 12:15 AM | Updated
05/06/2022 11:55 AM Does Pennsylvania have a gift tax? Pennsylvania
does not tax gifts made from detached or disinterested generosity.
However, transfers of cash or property in payment for services, or as
an inducement to perform services, are PA-taxable compensation and
therefore subject to the personal income tax.
From your question:
I live in Washington State. I received a large, one-time monetary gift
from my parents (>>$15k) who live in Pennsylvania.
If the gift was from both parents the limit is doubled before they have to pay Federal gift tax. Also in 2022 the limit changed.
According the the FAQ from the IRS:
How many annual exclusions are available?
The annual exclusion applies to gifts to each donee. In other words,
if you give each of your children $11,000 in 2002-2005, $12,000 in
2006-2008, $13,000 in 2009-2012 and $14,000 on or after January 1,
2013, the annual exclusion applies to each gift. The annual exclusion
for 2014, 2015, 2016 and 2017 is $14,000. For 2018, 2019, 2020 and
2021, the annual exclusion is $15,000. For 2022, the annual exclusion
is $16,000.
What if my spouse and I want to give away property that we own together?
You are each entitled to the annual exclusion amount on the gift.
Together, you can give $22,000 to each donee (2002-2005) or $24,000
(2006-2008), $26,000 (2009-2012) and $28,000 on or after January 1,
2013 (including 2014, 2015, 2016 and 2017). In 2018, 2019, 2020 and
2021, the total for you and your spouse is $30,000. In 2022, the total
for you and your spouse is $32,000.
That quote means that for 2022 the limit is now $16,000 or $32,000 an increase of $1000/$2000.