Honeycomb can be made with honey or molasses but the flavor will not be the same.
There isn't a US equivalent - we have molasses, but it's darker.
You can substitute corn syrup in recipes where it isn't the principal ingredient, but here that would not work.
That being said, my local grocery store has a British food section which carries golden syrup.
You probably don't have to substitute, you just need to find it in your local grocer.
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I use Golden Syrup, here in the US, all the time; I find it in the regular baking section, but I have seen it, like the previous answer, in the international section.
I'm sure it's the same in the UK, but here it now comes in easy-pour plastic bottles (just in case you were looking for it in different packaging), rather than only in tins like I used to buy (centuries ago) at the British NAAFI in Rheindahlen, Germany.
I have actually substituted it for corn syrup (my nephew is allergic to corn) w/
great results (you must stir constantly when making peanut brittle because it burns faster, but it still makes great brittle, & it makes a slightly softer truffle, but not enough that most would notice), so I'd be interested to hear what happened if you still cannot find Golden Syrup in your area and did use corn syrup...
perhaps you'd have to add some cane sugar, to keep it from being too stiff (ahem)?
I'm not a food chemist, obviously , but I do like to experiment with food & was happily surprised by my results.
My other answer would be "Amazon.
They have everything."
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make your own golden syrup by boiling sugar and water and add a little lemon juice to stop it crystalizing there are a few videos on youtube to show you how its made well easy hope
this helps another brit now living in the usa
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I had never heard of golden syrup and found these when I googled it.
You can order it online, for example from King Arthur .
And you can make your own as in this video .
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I find it odd when people say there's no equivalent in the USA, I beg to differ .
We have Golden Eagle Brand golden syrup since 1928 that's made right here by hand to this day.
It's made in Fayette, Alabama
and it's far superior to Lyle's.
You can order it online
it's $3 a pint!!
You can order it in the 16 oz or all the way up.
I usually purchase the 32 oz for $6.
If you haven't tried it please do!!
Check out their Facebook page GOLDEN EAGLE SYRUP.
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In the U.S.A. you can buy Lyles Golden Syrup (11.46 ounce) in the International Foods section at Publix.
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just make your own...
its simple and for 1/4 price
cooking.stackexchange.com/users/39780/Alison 
Having recently moved from UK to US, when making honeycomb, what should I use as a replacement for Golden Syrup?
What is the US equivalent of Golden Syrup (UK)?
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<syrup><sweeteners>
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cooking.stackexchange.com/users/24768/Sam Thompson
Some Americans are more familiar with honeycomb, corn syrup or molasses, but Golden Syrup is available online or in the international food section of many grocery stores. There are a number of products than can replace golden syrup in recipes. However, in the USA , this is not necessary as the British and American version are available in stores and online. An alternative is to make to make your own golden syrup using sugar, water and lemon juice.
Honey or molasses can be used to replace golden syrup in recipes but they may change the taste. Golden syrup, both the British and the US version, is available in the USA so there is no need to substitute. You can make your own golden syrup with sugar, water and lemon juice.