Cashless visit to the USA?

There's a few places where you may encounter difficulties:

• Lots of people expect tips in hotel, especially bellhops (the people who will carry your luggage to your room or into your car). I'm not sure about valets (those who park your car for you), I don't drive. Having a small quantity of one-dollar bills is always useful for those cases. In most other situations were tips are expected (restaurants, bars...) you can just include it on the receipt (when they don't do it for you).

• Gas stations often have automated systems which are not always compatible with foreign cards (they may ask for things like your ZIP code for security, and that gets lost in translation, for instance). But you should be able to pay at the counter in that case.

Other than that, I believe in most places a credit card will work (when it's not actually required).

However, I strongly recommend you have at least two independent cards. See this answer for the many reasons why.

Almost. I also live cashless at home but usually bring some cash while travelling, either exchanged before hand or via an ATM if needed.

For the US, it is mostly easy to pull with two exceptions:

• As @jcaron mentioned: Tips. Cash tips are often expected for help that has no other transaction. For tips with a transaction, you can usually add the amount on the bill itself when there is a separate line for that, which is seen frequently in restaurants. Taxis with machines now allow you to enter the tip as well. Still, it leaves some cases where people expect a tip for service but they is no way to pay it electronically.
• Tolls: Some highways, bridges and tunnels in the US require tolls. While there are many that can be paid electronically via an automated system, it may not be available on your rental car and the only other way to pay is cash. I passed along several a little over one year ago in the Northern US.

Gas stations were a problem until several years ago but I have no encountered any issues in the last 5 years with about 2-3 trips to the US annually.

Some things not mentioned by others about using your credit and debit cards in the US:

• Maestro cards don't work for purchases. You'll only be able to use these at ATMs to get cash.
• If you have a Visa Debit/Debit MasterCard and you use it at a payment terminal in the US, in some cases the terminal may ask the question "Debit or Credit". Always select Credit in this case (which actually means Visa/MC/AMEX/Discover/etc). "Debit" here refers to an old US-specific debit card network that predates Visa/MC debit cards.
• Most payment terminals accept contactless (though in many places the merchant won't even be aware of this, and most Americans don't even have contactless cards yet) so you may find this more convenient than using the chip in various situations.

I also feel the need to reiterate the advice to bring two different cards issued by two different banks. On rare occasions a card will inexplicably fail at a specific merchant for some obscure technical reason, and you will want to have another card to use if that happens.

If you're in a major city, or a minor one, or even in a small town, you'll have no problem finding places to eat where you can pay with your card. Cash only restaurants and food trucks do exist but they're uncommon and they generally warn everyone with some sort of signage.

Take out some cash. Cash-free living may be harder for visitors than for residents, although it depends a lot on your spending pattern. As a visitor, your spending pattern is different than as a resident, and you might do some things that some residents who have lived cash-free for years rarely or never do. You may need more cash more frequently than a resident, or less frequently. Some examples of when I needed cash as a visitor follow. The situation may have changed, so I added timestamps.

When I was visiting the USA for a workshop in May 2019, most workshop participants would fetch lunch at food trucks parked out in the street. Some food trucks took cards, most didn't. I seem to recall one Nordic participant sought out those food trucks that took cards because he had no cash at all.

When I was on vacation in Texas in December 2014, there was a major power outage and shops were without electricity. At this time they accepted only cash. Unlikely, but can happen.

Some urban transit may be de facto cash only, exact change only. Perhaps there are machines where you pre-pay a ticket electronically, but not at your stop. Perhaps most commuters use a transit card you don't have. Note that I have experienced this in Sweden as well (Summer 2012, Luleå).

I took a long-distance bus in California in May 2013, payments (which were in the order of $50) were cash only (Eastern Sierra Transit Authority, Bishop CA to Reno NV, incidentally the technically worst bus I've ever been on, very old, very noisy, no seatbelts). They also didn't issue any receipts so I could not claim this money back from my employer.

When I entered the US by a land border in 2014, I had to pay cash.

It also happened at least once to me (I think Iowa 2013) that my Swedish Visa Electron card wasn't working in a restaurant, I didn't have enough cash, the in-store ATM didn't take my European card, and I had to run to a nearby bank to get cash.

Note that even if you can live cashless, per-transaction fees for many payments with a Swedish card may accumulate, and it may be cheaper to use cash for small payments. Check how your foreign transaction fees work: is it strictly a % or is there a per-transaction fee as well? With my Dutch card, I paid at least €0.15 (IIRC) per POS transaction, which is OK when paying $50 for groceries or restaurant but wasteful when paying $1 5 times a day for small items. If all your costs are reimbursed this is SEP.

Apart from carrying at least two sufficiently different payment cards, I would recommend to carry at least some cash as a backup, probably the amount for a restaurant meal. Electronic payments can fail, and not everybody accepts them.

A lot of people here from Americans. We don't use ATM cards in Sweden; we use Visa/Mastercard (Credit or Debit), with youths offered Maestro instead.

There is one thing they have not mentioned that affects some of us Swedes (myself included). If you have any special letters in your name, you might not be able to pay with your card in some stores. My surname contains the letter ö, which when I swiped my card at a Target crashed all POS machines causing a long holdup while they had to reboot their system (and a second crash when they asked me to swipe the same card again). Luckily, my second card stored my surname using an o instead.

I would bring 3 or 4 different cards (Visa/MC from different banks).

Note for Americans: typically withdrawing cash from a Swedish debit card carries larger fees than the foreign exchange rate from using credit card (and you will pay the exchange rate, too). If you exchange cash for US dollars, the exchange rate will be even worse. The usual exchange rate on credit cards is 1.5% (at least on cards issued by mainstream banks), with several free alternatives available (such as the Revolut card which also offers limited free withdrawals).

I have always had a little extra cash with me while traveling to the US, but I did not end up using much of it (I still have cash left over from my first trip to the US more than 10 years ago).

Aside from hotel tipping, and a small number of government-driven fees (like park entrance fees), you can live in the US without cash.
Although I typically carry about 25 $ in cash, just for emergencies, it turns out to be the same bills since years, as I never need them.

Late last year we spent two weeks on a roadtrip through FL and in San Francisco, from that experience I'd say you can live cashless 98% of the time. The only time we needed cash was:

• tip in the hotel
• one "hipster" restaurant
• booking the airport express in SF

One important note I'm missing in this thread:

Your VISA may be capped at a max no. of transactions per day!

We experienced that our VISA is capped at 10 transactions per day. According to our bank this is a restriction from VISA directly and cannot be changed. So better bring one or two spare credits cards.

Locally: Public transit is cash only (unless you have a weekly or monthly pass), exact change required. Taxis take credit cards but charge you an extra $3 to do so.

The closest national park accepts cards but the link is poor enough that they have a sign up about cash being faster. In the not too distant past I have seen cash only signs at some park gates--the basic problem is they are often remote. Don't be confused by people apparently using cards at such gates--passes are credit card sized and are merely checked against one's ID, not processed. (Don't try to get one--if you somehow managed it would be useless.)

In most establishments this is perfectly acceptable and is increasingly so. Some "mom and pop" style restaurants may still be cash only, but that seems to be fewer and fewer. If you are gambling in a casino they typically prefer cash.

Rental car and hotels tend to prefer credit.

With the advent of square and fast mobile internet the barrier for accepting virtual payments has been all but eliminated. Given that you are going to a conference you are likely to be in a place that most merchants will accepting credit. Some more rural locations may still prefer cash, but they typically do not host conferences.