user78: Where can I get a time series of (date, bitcoin price in USD)? BitcoinCharts no longer provide historic data, only the last 20,000 samples.

user5964: Bitcoincharts recently retricted the download for latest 20000 trades, it basically represents only two days of tick data. 
Guys, if you have downloaded it before the restriction, would you mind sharing those past tick data? It would help me a lot.
Thanks!
Update:
As promised, I'm sharing the way how I downloaded all historical trade-by-trade data from MtGox. Firstly, register at BigQuerry cloud database, at this time only download of 16k rows of data is enabled. Secondly go to bitbucket.org/nitrous/bq and download the software which automatize the data download. The whole database took approx one hour to download. Everything is free, no charges. Enjoy!

user5978: This explains how to get a dump of past Mt Gox data and the Mt Gox API allows current data. Hope this helps!

user38618: Yes, there are websites to do that.

coincap.io
coinmarketcap.com (Most used)
bitinfocharts.com (Most advanced)


user26873: You didn't state what format you are looking for. Investing.com has a decent tool for this. I've used it for calculating long term gains/losses. 
https://www.investing.com/currencies/btc-usd-historical-data
EDIT:
Your updated question asked for JSON. 
I would use blockchain.info 
https://api.blockchain.info/charts/market-price?format=json&timespan=all
Other timespan options: 
&timespan=30days
&timespan=60days
&timespan=180days
&timespan=1year
&timespan=2years

user63978: You might want to try http://www.cryptodatasets.com/ It has free raw(every trade by trade) data and sampled data from Bitfinex and HitBtc (non from MtGox since its not operating anymore).
P.S. it's my website

user6693: Try quandl!
and search for "bitcoin"
for example:
http://www.quandl.com/BITCOIN-Bitcoin-Charts/MTGOXUSD-Bitcoin-Markets-mtgoxUSD

user11946: You can download the whole historical data (every single trade) from the various exchanges as a single .csv file here:
http://api.bitcoincharts.com/v1/csv/

user5: EDIT: These links appear to no longer work

You can get it at Bitcoincharts:
http://bitcoincharts.com/t/trades.csv?symbol=SYMBOL[&start=UNIXTIME][&end=UNIXTIME]

It returns a CSV file with the format:unixtime,price,amount. 
For example, you can use this link to get the MtGox prices since August:
http://bitcoincharts.com/t/trades.csv?symbol=mtgoxUSD&start=1312174800


78: <p>Where can I get a time series of (date, bitcoin price in USD)? BitcoinCharts no longer provide historic data, only the last 20,000 samples.</p>
 5964: <p>Bitcoincharts recently retricted the download for latest 20000 trades, it basically represents only two days of tick data. </p>

<p>Guys, if you have downloaded it before the restriction, would you mind sharing those past tick data? It would help me a lot.
Thanks!</p>

<p><strong>Update:</strong></p>

<p>As promised, I'm sharing the way how I downloaded all historical trade-by-trade data from MtGox. Firstly, register at BigQuerry cloud database, at this time only download of 16k rows of data is enabled. Secondly go to bitbucket.org/nitrous/bq and download the software which automatize the data download. The whole database took approx one hour to download. Everything is free, no charges. Enjoy!</p>
 5978: <p><a href="https://bitcointalk.org/index.php?topic=218980.0" rel="nofollow">This</a> explains how to get a dump of past Mt Gox data and the <a href="https://bitbucket.org/nitrous/mtgox-api/overview" rel="nofollow">Mt Gox API</a> allows current data. Hope this helps!</p>
 38618: <p>Yes, there are websites to do that.</p>

<ul>
<li><p><a href="https://coincap.io" rel="nofollow noreferrer">coincap.io</a></p></li>
<li><p><a href="https://coinmarketcap.com" rel="nofollow noreferrer">coinmarketcap.com</a> (Most used)</p></li>
<li><p><a href="https://bitinfocharts.com" rel="nofollow noreferrer">bitinfocharts.com</a> (Most advanced)</p></li>
</ul>
 26873: <p>You didn't state what format you are looking for. Investing.com has a decent tool for this. I've used it for calculating long term gains/losses. </p>

<p><a href="https://www.investing.com/currencies/btc-usd-historical-data" rel="nofollow noreferrer">https://www.investing.com/currencies/btc-usd-historical-data</a></p>

<p>EDIT:
Your updated question asked for JSON. 
I would use blockchain.info </p>

<p><code>https://api.blockchain.info/charts/market-price?format=json&amp;timespan=all</code></p>

<p>Other timespan options: </p>

<p><code>&amp;timespan=30days</code><br>
<code>&amp;timespan=60days</code><br>
<code>&amp;timespan=180days</code><br>
<code>&amp;timespan=1year</code><br>
<code>&amp;timespan=2years</code></p>
 63978: <p>You might want to try <a href="http://www.cryptodatasets.com/" rel="nofollow noreferrer">http://www.cryptodatasets.com/</a> It has free raw(every trade by trade) data and sampled data from Bitfinex and HitBtc (non from MtGox since its not operating anymore).</p>

<p>P.S. it's my website</p>
 6693: <p>Try <a href="http://www.quandl.com/" rel="nofollow">quandl</a>!
and search for "bitcoin"</p>

<p>for example:
<a href="http://www.quandl.com/BITCOIN-Bitcoin-Charts/MTGOXUSD-Bitcoin-Markets-mtgoxUSD" rel="nofollow">http://www.quandl.com/BITCOIN-Bitcoin-Charts/MTGOXUSD-Bitcoin-Markets-mtgoxUSD</a></p>
 11946: <p>You can download the whole historical data <strong>(every single trade)</strong> from the various exchanges <strong>as a single .csv file</strong> here:</p>

<p><a href="http://api.bitcoincharts.com/v1/csv/" rel="nofollow">http://api.bitcoincharts.com/v1/csv/</a></p>
 5: <p>EDIT: These links appear to no longer work</p>

<hr>

<p>You can get it at <a href="http://bitcoincharts.com/about/markets-api/" rel="nofollow noreferrer">Bitcoincharts</a>:</p>

<pre><code>http://bitcoincharts.com/t/trades.csv?symbol=SYMBOL[&amp;start=UNIXTIME][&amp;end=UNIXTIME]
</code></pre>

<p>It returns a CSV file with the format:<code>unixtime,price,amount</code>. </p>

<p>For example, you can use this link to get the MtGox prices since August:</p>

<pre><code>http://bitcoincharts.com/t/trades.csv?symbol=mtgoxUSD&amp;start=1312174800
</code></pre>
